bise rawalpindi past paper _2nd year_ physics 2006-2015

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PPhhyyssiiccss--IIII (2006-2015)

PPhhyyssiiccss--IIII 2006

(Subjective Type-46 Marks)

Section-I (Short Questions)

Q: 1 Write short answers of any EIGHT questions. (8x2=16)

(i) Will bright light eject more electrons from a metal surface than dimmer light of the same colour?

(ii) If the absolute potential at a point is zero, what can you say about the electric intensity there?

(iii) What is Xerography?

(iv) An ordinary bulb is marked 60 watt, 200 volt, what is its resistance?

(v) Can an electron at rest be set in motion with a magnet?

(vi) A sensitive galvanometer cannot be stable? Why?

(vii) What is meant by Inductive reactance?

(viii) What are extrinsic semiconductors?

(ix) What factors make a fusion reaction difficult to achieve?

(x) How the reception of a particular radio station is selected on your radio set?

(xi) What is meant by amplitude modulation?

(xii) It is more difficult to start a fusion reaction, than a fission reaction. Why?

Section-II (Essay Type)

Attempt any THREE questions from this section. (3x10=30)

Q: 2 (a) Prove that RC = t.

(b) Find an expression for the energy stored in a capacitor.

(c) Determine the electric field at position r��⃗ =(4i�+ 3j�) m caused by a point charge q = 5 x 10-6 C placed

at the origin.

Q: 3 (a) Define magnetic flux and flux density.

(b) Explain the principle, construction and working of a moving coil galvanometer.

(c) How fast must a proton move in a magnetic field of 2.50 x 10-3 T such that the magnetic force is equal

to its weight?

Q: 4 (a) What is the effect of Forward biasing and reverse biasing of a p-n junction diode on its resistance?

(b) Describe the working of a NPN transistor as an amplifier and find an expression for its voltage gain.

(c) The current flowing into the base of a transistor is 100 µA. Find its collector current IC, its emitter

current IE. The current gain β = 100.

Q: 5 (a) Define black body.

(b) Define photoelectric effect. Write down main results of photoelectric effect.

(c) X-rays of wavelength 22 Pm are scattered from a carbon target. The scattered radiations being

viewed at 85° to the incident beam. What is Compton shift?

Q: 6 (a) Discuss quantized energies of the electron in the Bohr’s orbit.

(b) What do you mean by LASER? Write one property.

(c) A hydrogen atom is in its ground state (n = 1).Using Bohr’s theory, calculate

(i) The radius of the orbit. (ii) The linear momentum of the electron.

(Objective Type-29 Marks)

Q: 7 Encircle the correct answer. (10x1=10)

(i) Electric lines of force can never _____________.

(ii) Semiconductor diode is an example of _____________.

(iii) The S.l. Unit of magnetic induction is _____________.

(iv) Lenz’s law is in accordance with law of conservation of _____________.

(v) At high frequency, current through a capacitor will be _____________.

(vi) A hole in a P-type semi-conductor is _____________.

(vii) Rectification is the process of converting, _____________.

(viii) The converse of pair production is _____________.

(ix) When an electron is in its lowest energy state, it is called _____________.

(x) The particles equal in mass or greater then proton are _____________.

Q: 8 Complete the following sentences. (10x1=10)

(i) Electron volt is a unit of _____________.

(ii) The third digit on the carbon resistor is _____________.

(iii) The working of galvanometer depends on _____________ exerted on the coil.

(iv) A transformer depends upon _____________ voltage for its operation.

(v) A metal detector consists of inductor and _____________.

(vi) Such substances which undergo plastic deformation until they break are known as _____________.

(vii) When collector and emitter behave as two terminals, the transistor can be used as a _____________.

(viii) The mass of a body in motion is _____________ than the mass of a body when it is at rest.

(ix) The continuous spectrum is obtained due to _____________ of impacting electrons.

(x) Beta particles are fast moving _____________ emitted from the nucleus of radioactive element.

Q: 9 Match Column A with Column B. (9x1=9)

COLUMN A COLUMN B

Electric charges Repel each other

A. C. Generator uses Split rings

The minimum charge on an object can be 1.6 x 10-19 C

The building blocks of matter are Quarks

Laser light Coherent

Thermistor can be used as Temperature sensor

The wire receiving the wave is called Receiving antenna

0.693

λ Half life of a radioactive element

Each crystalline solid has Definite melting point


(Subjective Type-46 Marks)


Q: 1 Write short answers of any EIGHT questions. (8x2=16)

(i) What are the difficulties in testing whether the filament of a lighted bulb obeys Ohm’s law?

(ii) If a point charge q of mass m is released in a non-uniform electric field, will it make a rectilinear motion?

Explain.

(iii) Why is B non-zero outside a solenoid?

(iv) Four unmarked wires emerge from a transformer. What steps would you take to determine the turn ratio?

(v) How the reception of a particular radio station is selected on your radio set?

(vi) In an R-L circuit, will the current lag or lead the voltage? Illustrate your answer by a vector diagram.

(vii) What are amorphous and polymeric solids?

(viii) What are superconductors? Explain.

(ix) Why charges are not present in the depletion layer?

(x) What happens to total radiations from a black body if its absolute temperature is doubled?

(xi) What do we mean when we say that the atom is excited?

(xii) A particle which produces more ionization, is less penetrating. Why?



Q: 2 (a) Define electric potential energy.

(b) Derive an expression for absolute potential at a certain point due to a point charge.

(c) Two point charges, q1 = -1.0 x 10-6 C and q2 = +4.0 x 10-6 C are separated by a distance of 3.0 m.

Find and justify the zero field location.

Q: 3 (a) State Faraday’s law of electromagnetic induction.

(b) Find expression for energy stored in an inductor in terms of inductance L and current I.

(c) The back emf in a motor is 120 V, when the motor is running at 1680 r.m.p. What is the back emf

when the motor is running at 3360 r.m.p.?

Q: 4 (a) Define Young’s modulus.

(b) What is strain energy? Derive relation for strain energy in deformed materials.

(c) A 1.25 cm diameter cylinder is subjected to a load of 2500 Kg. Calculate the stress on the bar.

Q: 5 (a) Differentiate between special theory of relativity and general theory of relativity.

(b) Discuss the wave nature of particles. How this idea was confined by Davisson and Germer?

(c) An x-ray of wave length 22 Pm was scattered by a carbon target. The scattered radiation being

viewed at 85° to the incident beam. What is Compton shift? (h = 6.63 x 10-34 Js)

Q: 6 (a) Write the names of any four basic forces of nature.

(b) Define nuclear fission. How can we start and control the fission process? Discuss in detail.

(c) The half life of 38 Sr 91 is 9.7 hours. Find its decay constant.

(Objective Type-29 Marks)

Q: 7 Encircle the correct answer. (10x1=10)

(i) S.l. unit of electric flux is _____________.

(ii) Maximum power delivered by battery is _____________.

(iii) When charged particle enters magnetic field, it moves in _____________.

(iv) In step up transformer _____________.

(v) The mathematical notation for NOR gate is _____________.

(vi) Wave nature of light appears in _____________.

(vii) Angular momentum of electron in nth orbit is _____________.

(viii) One gray (Gy) is equal to _____________.

(ix) In capacitive circuit, current leads the voltage by _____________.

(x) Curie temperature for iron is about _____________.

Q: 8 Complete the following sentences. (10x1=10)

(i) Total flux through a closed surface does not depend upon _____________ of the close surface.

(ii) Semiconductors diodes are example of _____________ device

(iii) F ��⃗ =q E ��⃗ + q( V ��⃗ × B ��⃗ ) is called _____________ force

(iv) When the motor is just started, back emf is almost _____________.

(v) The highest value reached by voltage or current in one cycle is called _____________.

(vi) Since strain is ratio of length, so it is dimensionless and has no _____________.

(vii) The electronic circuits which implement the various logic operations are known as _____________.

(viii) The magnetic conducting lens concentrates the beam from an electron gun on to the _____________.

(ix) In Helium-Neon Laser, the percentage of Helium is _____________.

(x) Geiger counter is not suitable for _____________ counting.

Q: 9 Match Column A with Column B. (9x1=9)

COLUMN A COLUMN B

Unlike charges Attractive force

Reciprocal of resistivity Conductivity

Conversion of electrical energy to Mechanical energy

Motor

Reactance of a capacitor is Xc=1

ωC

Change in volume per unit volume Volumetric Strain

�� ⁄ for a transistor is called Current gain

Energy of the photon Hf

Radius of first Bohr’s orbit for hydrogen 0.53 A°

Half life of Uranium 239 is 23.5 Minutes


Time: 20 minutes (Objective Type) Marks: 17

Q: 1 Encircle the correct option. (17x1=17)

(i) S.l. unit of charge is _____________.

(A) Ampere (B) Volt (C) Coulomb (D) Calorie

(ii) Charge on an electron was determined by S.l. units of charge is _____________.

(A) Max well (B) Ampere (C) Bohr (D) Millikan

(iii) Electrical energy is measured in _____________.

(A) Kilowatt (B) Horse power (C) Watt (D) Kilo Watt-hour

(iv) A 100 watt bulb is operated by 200 volt, the current flowing through the bulb is _____________.

(A) 0.5 A (B) 1 A (C) 2 A (D) 2.5 A

(v) A charged particle moving in a magnetic field experiences a resultant force, _____________.

(A) In the direction of the field (B) In the direction of its motion

(C) In the direction opposite to its motion (D) In the direction perpendicular to field and its motion

(vi) The unit of magnetic flux is _____________.

(A) Weber (B) Henry (C) wb m2 (D) None

(vii) S.l. unit of impedance is _____________.

(A) Hertz (B) Henry (C) Ohm (D) Ohm-meter

(viii) The total reactance of a series R-L-C circuit at resonance is _____________.

(A) 1 (B) Zero (C) Infinity (D) Equal to the resistance

(ix) Substances which break just after the elastic limit is reached are called _____________.

(A) Ductile (B) Hard (C) Soft (D) Brittle Substance

(x) A circuit which converts low voltage to high voltage is called _____________.

(A) Amplifier (B) Rectifier (C) Transistor (D) Inductor

(xi) An Op-Amp can be used as a _____________.

(A) Comparator (B) Inverting amplifier (C) Non inverting amplifier(D) All of these

(xii) At low temperature, a body usually emits radiation of _____________.

(A) Long wavelength (B) Short wavelength (C) Infinite wavelength (D) None of these

(xiii) The platinum wire becomes white at a temperature of _____________.

(A) 500 °C (B) 1600 °C (C) 1100 °C (D) 900 °C

(xiv) The diameter of an atom is of the order of _____________.

(A) 10-12 m (B) 10-10 m (C) 10-4 m (D) 10-8 m

(xv) Specially designed solid state detector can be used to detect _____________.

(A) β-rays (B) α-rays (C) γ-rays (D) X-rays

(xvi) Thyroid cancer is cured by _____________.

(A) Carbon-14 (B) Iodine-131 (C) Cobalt-60 (D) Sodium-24

(xvii) Which one of the radiation is extremely penetrating _____________.

(A) β-rays (B) α-rays (C) γ-rays (D) None of these

Time: 3:10 hours (Subjective Type) Marks: 68


Q: 2 Write answers of any TWENTY TWO questions. (22x2=44)

(i) Electric lines of force never cross. Why? (ii) Do electrons tend to go to region of high potential or low potential? (iii) Describe the force or forces on a positive point charge when placed between parallel plate with similar

and equal charges. (iv) Name a circuit which give a continuously varying potential and give its relation. (v) Is the filament resistance lower or higher in a 500 W, 220 V light bulb than in a 100 W, 220 V bulb? (vi) Do bends in a wire affect its electrical resistance? (vii) How can you use a magnetic field to separate isotopes of chemical elements? (viii) Why does the picture on a T. V. screen become distorted when a magnet is brought near the screen? (ix) Why the resistance of an ammeter should be very low? (x) Define induced emf induced current. (xi) What is motional EMF? (xii) State Lenz’s Jaw (xiii) Define D. C. Generator and D. C. Motor. (xiv) Define peak to peak value and root mean square (rms) value. (xv) Draw a block diagram of common type of metal detector. (xvi) What are polymeric solids? (xvii) Define FM and draw its diagram. (xviii) Define Young’s modulus and Shear modulus. (xix) Draw a diagram of exclusive OR gate. (xx) Why ordinary silicon diodes do not emit light? (xxi) What is the net charge on a n-type or p-type substances? (xxii) Why photo diodes are operated in reverse biased state? (xxiii) What do you mean by E = mc2? (xxiv) Give the four application of photocell. (xxv) Will higher frequency light eject greater number of electrons than low frequency light? (xxvi) We do not notice the de-Broglie wavelength for a pitched cricket ball. Why? (xxvii) Is it possible to create a single electron from energy? Explain. (xxviii) Which has lower energy quanta? Radio waves or X-rays (xxix) What is de-Broglie’s interpretation of Bohr’s orbit? (xxx) Why does electron exist outside of nucleus but in atom? (xxxi) Is energy conserved when an atom emits a photon of light? (xxxii) Write a note on Hadrons. (xxxiii) How many ways radiation interact with matter?



Q: 3 (a) State and explain Coulomb’s law. (b) Two point charges, q1 = -1.0 x 10-6 C and q2 = +4.0 x 10-6 C are separated by a distance of 3.0 m. Find and justify the zero field location. Q: 4 (a) Determine charge to mass ratio (e/m) of an electron. (b) A power line 10 m high carries a current 200 A. Find the magnetic field of the wire at the ground. (µo = 4π x 10-7 wb A-1 m-1) Q: 5 (a) How an AC current flows through a capacitor? Write the relation between charge on a capacitor and voltage across its plates. Also write an expression for capacitor reactance. (b) A circuit has an inductance of 1/π H and resistance of 2000 Ohms. A 50 Hz AC is supplied to it. Calculate the reactance and impedance offered by the circuit. Q: 6 (a) Describe Davisson and Germer Experiment to confirm the wave nature of electrons. Also calculate expression for wavelength. (b) What is the de-Broglie wavelength of an electron whose KE is 120 eV? The value of Plank’s constant is 6.625 x 10-34 Js. Q: 7 (a) Explain nuclear fission. Also define chain reaction. (b) A sheet of lead 5.0 mm thick reduces the intensity of a beam of γ - rays by a factor 0.4. Find half value thickness of lead sheet which will reduce the intensity to half of its initial value.




(i) The S.l. unit of permittivity is _____________.

(A) N m2 C-2 (B) C2 N-1 m-2 (C) N m C-2 (D) N m2 C-1

(ii) One coulomb of charge is created by _____________.

(A) 10 e- (B) 6.25 x 1018 e- (C) 6.25 x 1021 e- (D) 1.6 x 10-19 e-

(iii) The electrical analog of mass is electricity is _____________.

(A) Capacitance (B) Inductance (C) Charge (D) Resistance

(iv) Which one of the following represents Ohm’s law _____________.

(A) V = I R (B) I = V / R (C) R = V / I (D) All of these

(v) The energy resides in a current carrying conductor in the form of strain in the _____________.

(A) Magnetic field (B) Electrostatic field (C) Gravitational field (D) All of these

(vi) Which one of the following relations is correct?

(A) 1 wb m-2 = N m-1 A-1 (B) 1 Tesla = 104 Gausses

(C) 1 wb m-2 = 1 Tesla (D) All of these

(vii) Which one of the following permits direct current to flow easily?

(A) Resistance (B) Capacitance (C) Inductance (D) None of these

(viii) One Henry is equal to _____________.

(A) 1 Ohm x 1 Sec (B) 1 Ohm x 1 Meter (C) 1 Ohm x 1 Coulomb (D) None of these

(ix) AC can be measured by using _____________.

(A) Heating effect (B) Magnetic effect (C) Chemical effect (D) None of these

(x) Which one is correct for a step down transformer?

(A) Np > Ns (B) Np < Ns (C) Np = Ns (D) None of these

(xi) If Io is the peak value of A. C. current, its average value over the complete cycle is _____________.

(A) Io�2

(B) √2 Io (C) √2

Io (D) Zero

(xii) At resonance, the phase angle for RLC series resonance circuit equals _____________.

(A) 0° (B) 90° (C) 180 ° (D) 270°

(xiii) Which of the following has least energy gap?

(A) Conductor (B) Insulator (C) Semi Conductor (D) None

(xiv) When the emitter-base junction of a transistor is reversed biased, collector current _____________.

(A) Reverses (B) Increases (C) Decreases (D) Stops

(xv) The virtual mass of photon is _____________.

(A) Zero (B) m = hf / c (C) m = hf / c2 (D) m = c2 / hf

(xvi) Hydrogen is also called _____________.

(A) Deuterium (B) Tritium (C) Protium (D) All these

(xvii) The particle which has its mass number and charge number equal to zero is _____________.

(A) Proton (B) Electron (C) Neutron (D) Photon




(i) How can you identify that which plate of capacitor is positively charged? (ii) Give the statement of Coulomb’s law. (iii) Electric lines of force never cross. Why? (iv) Define electron volt. (v) Do bends in a wire affect its electrical resistance? Explain. (vi) Give the statement of Kirchhoff’s first rule. (vii) What do you understand by Thermistor? (viii) Why the resistance of an ammeter should be very low? (ix) Why the voltmeter should have very high resistance? (x) What is meant by DMM? (xi) How can a current loop be used to determine the presence of a magnetic field in a given region of space? (xii) Does the induced emf always act to decrease the magnetic flux through a circuit? (xiii) How would you position a flat loop of wire in changing magnetic field so that there is no emf induced in

the loop? (xiv) Define Henry. (xv) In a transformer, there is no transfer of charge from primary to secondary. How is then power transferred? (xvi) Name the device that will permit the flow of AC but not the DC. (xvii) How does doubling the frequency affect the reactance of a capacitor? (xviii) Define impedance. (xix) What is meant by Hysteresis loss? (xx) Distinguish between intrinsic and extrinsic semiconductors. (xxi) What is meant by strain energy? (xxii) Why is the base current in a transistor very small? (xxiii) Why charge carriers are not present in depletion region. (xxiv) What is meant by forward biased PN-Junction? (xxv) Can pair production take place in vacuum? Explain. (xxvi) Define relative motion. (xxvii) When does light behave as a wave? (xxviii) Why laser action could not occur without population inversion between atomic levels? (xxix) What is meant by line spectrum? (xxx) How can the spectrum of Hydrogen contain so many lines when Hydrogen contains one electron? (xxxi) Why are heavy nuclei unstable? (xxxii) A particle which produces more ionization is less penetrating. Why? (xxxiii) What factors make a fusion reaction difficult to achieve?



Q: 3 (a) Define capacitance of a capacitor. Derive the formula for the capacitance of a parallel plate capacitor.

(b) Find the electric field strength required to hold suspended a particle of mass 1.0 x 10-6 kg and charge

1.0 µC between two plates 10 cm apart.

Q: 4 (a) What is Ampere’s law? Calculate the magnetic field due to current flowing through a solenoid?

(b) What current should pass through a solenoid that is 0.5 m long with 10,000 turns of copper wire so

that it will have a magnetic field of 0.4 T?

Q: 5 (a) What are semi-conductors? How p-type and n-type materials are formed?

(b) A wire 2.5 m long and cross-section area 10-5 m2 is stretched 1.5 mm by a force of 100 N in elastic

limit. Calculate stress and Young’s modulus.

Q: 6 (a) Discuss Davison and Germer experiment to prove the wave nature of electron.

(b) What is the de-Broglie wavelength of an electron whose KE is 120 eV?

Q: 7 (a) What is a nuclear reactor? Describe four important parts of a reactor.

(b) Calculate the energy in MeV released in the following fusion reaction. H+ 12 H1

3 → He24 + n0

1




(i) Planck’s constant ‘h’ has the same units as that of _____________.

(A) Linear momentum (B) Angular momentum(C) Torque (D) Power

(ii) Helium-Neon Laser discharge tube contains Neon equal to _____________.

(A) 25% (B) 40% (C) 15% (D) 82%

(iii) Life time of electron in metastable state is about _____________.

(A) 10-5 sec (B) 10-3 sec (C) 10-8 sec (D) 10-2 sec

(iv) The chemical properties of any element depend on its _____________.

(A) Number of isotopes(B) Number of isobars (C) Atomic number (D) Mass number

(v) α-particles consist of _____________.

(A) Positively charged particles (B) Negatively charged particles

(C) Neutral particles (D) Photons

(vi) The process of combining low frequency signal with high frequency radio wave is called as __________.

(A) Modulation (B) Amplification (C) Demodulation (D) Resonance

(vii) A substance having empty conduction band is called as _____________.

(A) Semiconductor (B) Conductor (C) Insulator (D) Transistor

(viii) The reverse current through PN-Junction is _____________.

(A) Infinite (B) Zero

(C) Less than forward current (D) Greater than forward current

(ix) Photoelectric effect was explained by _____________.

(A) Hertz (B) Einstein (C) Rutherford (D) Bohr

(x) The galvanometer constant in a moving coil galvanometer is given by _____________.

(A) k = NB / cA (B) k = c / NAB (C) k = NAB / c (D) k = cA / NB

(xi) The torque acting on a current carrying coil is given by _____________.

(A) τ = NIAB cosα (B) τ = BIL sinα (C) τ = NIAB sinα (D) τ = BIL cosα

(xii) In the secondary coil of a step up transformer, the numbers of turns are given as _____________.

(A) Ns > Np (B) Ns < Np (C) Ns = Np (D) Ns ≤ Np

(xiii) The practical application of phenomenon of mutual induction is _____________.

(A) Electric motor (B) Transformer (C) AC generator (D) DC generator

(xiv) The electric force per unit charge is known as _____________.

(A) Electric flux (B) Electric Intensity (C) Electric potential (D) Electric volt

(xv) The capacitance of a parallel plate capacitor is given by _____________.

(A) C = A / εod (B) C = Aεo / d (C) C = εod / A (D) C = d / εoA

(xvi) A thermistor is a heat sensitive _____________.

(A) Capacitor (B) Diode (C) Resistor (D) Inductor

(xvii) Tolerance for Silver Band is _____________.

(A) ± 10% (B) ± 5% (C) ± 15% (D) ± 20%




(i) The potential is constant throughout a given region of space, if the electrical field is zero or non-zero in this region. Explain.

(ii) How can you identify that which plate of a capacitor is positively charged? (iii) Define capacitance of a capacitor. Write down its units. (iv) What are the difficulties in testing whether the filament of a lighted bulb obeys Ohm’s Law? (v) Is the filament resistance lower or higher in a 500 watt, 220 volt light bulb than in a 100 watt, 220 volt bulb? (vi) Write three uses of potentiometer. (vii) Why the resistance of an ammeter should be very low? (viii) How can you use a magnetic field to separate isotopes of chemical element? (ix) Write four uses of CRO. (x) What changes are required to convert DC motor into DC generator? (xi) Four unmarked wires emerge from a transformer. What steps would you take to determine the turn ratio? (xii) Show that ε and ∆Φ / ∆t have same units. (xiii) Differentiate between step-up and step-down transformers. (xiv) Differentiate between single phase & three phase AC supply. (xv) Capacitor allows the flow of AC but not DC. Explain why? (xvi) How does doubling the frequency affect the reactance of (a) an inductor (b) a capacitor? (xvii) Differentiate between diamagnetic & Ferro-magnetic materials. Give one example of each. (xviii) Define stress and strain. Also write their units. (xix) What is meant by hysteresis loss? How it is used in the construction of a transformer? (xx) Why is the base current in a transistor very small? (xxi) Why ordinary silicon diodes do not emit light? (xxii) Why a photodiode is operated in reverse biased state? (xxiii) What is photocell? Write its four uses. (xxiv) Does the dilation means that time really passes more slowly in moving system? Explain. (xxv) If an electron and a proton have the same de-Broglie wavelength, which particle has greater speed? (xxvi) Pair production cannot be observed in vacuum. Explain why? (xxvii) Differentiate between ground state, excited state and ionized state of an atom. (xxviii) Why laser action could not occur without population inversion between atomic levels? (xxix) Is energy conserved when an atom emits a photon of light? Explain. (xxx) What is radioactive tracer? Describe one application each in medicine and in industry. (xxxi) Describe briefly interaction of various types of radiations with matter. (xxxii) What are isotopes? What do they have common and what are their differences? (xxxiii) Differentiate between Leptons and Hadrons.



Q: 3 (a) What is capacitor? Calculate the energy stored in a capacitor and energy density. (b) The resistance of an iron wire at 0 °C is 1 x 104 Ohms. What is the resistance at 500 °C if the temperature co-efficient of iron is 5.2 x 10-3 K-1. Q: 4 (a) Define an ammeter. How a galvanometer is converted into an ammeter? (b) A solenoid has 250 turns and its self inductance is 2.4 mH. What is the flux through each turn when the current is 2 A? What is the induced emf when the current changes at 20 AS-1.

Q: 5 (a) Describe stress and strain. Develop the relation for Young’s, Bulk and Shear modulus. (b) Find the value of current and inductive reactance, When AC voltage of 220 volts at 50 Hz is passed through an inductor of 10 Henry. Q: 6 (a) What is operational amplifier? Explain op-amp as an inverting amplifier. (b) X-rays of wavelength 22 Pm are scattered from a carbon target. The scattered radiations being

viewed at 85° to the incident beam. What is Compton shift? Q: 7 (a) Using Bohr’s theory, calculate the radii and energies of quantized orbits. (b) Find the mass defect and the binding energy for tritium. Mass of tritium = 3.016049 u, Mass of proton = 1.007276 u, Mass of neutron = 1.008665 u




(i) The minimum energy required by a photon to create an electron and positron pair is _____________.

(A) 3 MeV (B) 2.4 MeV (C) 1.5 MeV (D) 1.02 MeV

(ii) Nuclear fission chain reaction is controlled by using _____________.

(A) Steel rods (B) Graphite rods (C) Cadmium rods (D) Platinum rods

(iii) A well known example of an intrinsic semi conductor is _____________.

(A) Germanium (B) Phosphorous (C) Aluminium (D) Cobalt

(iv) β-particles in Wilson cloud chamber have _____________.

(A) Circular path (B) Curved path (C) Elliptical path (D) Zigzag or Erratic path

(v) The unit of impedance is _____________.

(A) Ohm (B) Ohm-1 (C) Ohm m-1 (D) No unit

(vi) The amount of energy required to eject an electron, from metal surface is called _____________.

(A) Threshold frequency (B) Work function

(C) Pair production (D) Compton effect

(vii) When an area is held perpendicular to the field lines, then the magnitude of electric flux is ___________.

(A) Negative (B) Maximum (C) Minimum (D) Zero

(viii) One electric volt is equal to _____________.

(A) 2π / nh (B) nh / 2π (C) 2h / nπ (D) h / π

(ix) The numerical value of green colour in colour code carbon resistor is _____________.

(A) 0 (B) 3 (C) 5 (D) 8

(x) Production of x-rays can be regarded as the reverse phenomenon of _____________.

(A) Pair production (B) Photoelectric effect (C) Compton effect (D) Annihilation of matter

(xi) The orbital angular momentum in the allowed stationary orbits of Hydrogen atom is given by _________.

(A) (B) (C) (D)

(xii) If the conductivity of a material is high, then it is _____________.

(A) An insulator (B) A semi conductor (C) A good conductor (D) A super conductor

(xiii) The galvanometer can be made sensitive if the value of the factor C / BNA is _____________.

(A) Made large (B) Made small (C) Remains constant (D) Infinite

(xiv) The grief in the cathode ray oscilloscope _____________.

(A) Controls number of waves (B) Controls the brightness of spot formed

(C) Accelerates electrons (D) Has positive potential with respect to cathode

(xv) Energy density Um can be given by the relation _____________.

(A) 1 B2 / 2 µo (B) 2 B2 / µo (C) 1 µo / 2 B2 (D) 2 µo / B2

(xvi) The current gain β of a transistor can be given by _____________.

(A) IC / IB (B) IE / IC (C) IB / IE (D) IE / IB

(xvii) If we make magnetic field stronger, the value of induced current is _____________.

(A) Decreased (B) Increased (C) Vanished (D) Kept constant



Q: 2 Write answers of any FIVE questions. (5x2=10)

(i) The potential is constant throughout a given region of space. Is the electric field zero or non-zero in this region? Explain.

(ii) Is it true that Gauss’s law states that the total number of lines of forces crossing any closed surface in the outward direction is proportional to the net positive charge enclosed within surface?

(iii) Does the total flux depend upon the shape or geometry of the closed surface? (iv) Do bends in a wire affect its electrical resistance? Explain. (v) Is the filament resistance lower or higher in a 500 W, 220 V light bulb than in a 100 W, 220 V bulb? (vi) What does the equation H = I2RT show? (vii) A current in a conductor produces a magnetic field, which can be calculated by using Ampere’s law.

Since current is defined as the rate of flow of charge, what can you conclude about the magnetic field due to stationary charges? What about moving charges?

(viii) Why the resistance of an ammeter should be very low?


(i) Why should a voltmeter have a very high resistance? (ii) When magnetic flux through a closed circuit, having a galvanometer but no battery, is changed, all of a

sudden galvanometer shows a deflection, indicating that free charges in the circuit have gained some energy. Is it against law of conservation of energy? Give reasons in support of your answer.

(iii) Can an electric motor be used to drive an electric generator with output from the generator being used to operate the motor?

(iv) Why is split ring used in DC generator in place of slip rings? (v) Four unmarked wires emerge from a transformer. What steps would you take to determine turns ratio? (vi) At resonance frequency the impedance of RLC series circuit is only resistive. Why? (vii) How many times per second will an incandescent lamp reach maximum brilliance when connected to a

60 Hz source? (viii) What is meant by amplitude modulation (AM)?


(i) Distinguish between crystalline & amorphous solids. (ii) Define dia- and para-magnetic substances. Give examples of each. (iii) How the energy bands are formed in a solid? (iv) Why charge carriers are not present in the depletion region of PN-junction? (v) Why is base current in a transistor very small? Explain. (vi) What is photo-voltaic cell? Discuss its working. (vii) Which photon, red or blue, carries the most energy? Explain. (viii) Why do not we observe a Compton Effect with visible light? Explain.

Q: 5 Write answers of any SEVEN questions. (7x2=14)

(i) When does light behave as particles? Give two examples. (ii) What happens to the total radiation from black body if its absolute temperature is doubled? Explain. (iii) Is energy conserved when an atom emits a photon of light? Explain. (iv) What do we mean when we say that the atom is excited? (v) Mention and very briefly explain two uses of LASER. (vi) Define Nuclear Fission. Give two examples of such reaction. (vii) What do we mean by the term critical mass? (viii) State two of the characteristics of β-particle. (ix) Briefly describe the term radiography.



Q: 6 (a) State Gauss’s Law. Find electric intensity between two oppositely charged parallel plates. (b) A charge of 90 C passes through a wire in one hour and fifteen minutes. What is current in the wire?

Q: 7 (a) Derive an expression for the force acting on a current carrying conductor of length L placed in a uniform magnetic field of strength B. (b) A square coil of side 16 cm has 200 turns and rotates in a uniform magnetic field of 0.05 T. If the peak emf is 12 V. Determine the angular velocity of the coil.

Q: 8 (a) What is doping? Write a note on the formation of n-type and p-type semiconductors. (b) At what frequency will an inductor of 1.0 H have a reactance of 500 Ω?

Q: 9 (a) What is meant by rectification? Explain the action of a semiconductor diode as half wave rectifier. (b) What is the mass of a 70 kg man in a space rocket traveling at 0.8 c from us as measured from earth?

Q: 10 (a) What is a nuclear reactor? Describe its four important parts. (b) Compute the shortest wave-length radiation in the Balmer series? What value of “n” must be used?




(i) The smallest possible charge which a particle can have is _____________.

(ii) Which of the following units is different from the other?

(iii) If the current through a resistance is halved, then the _____________.

(iv) Charge in motion produces _____________.

(v) A charged particle moving in a magnetic field experiences a force given by

(vi) The value of shunt resistance required to convert a galvanometer into ammeter is

(vii) Henry is the unit of _____________.

(viii) The energy stored in an inductor is given by _____________.

(ix) Reactance of a capacitor is given by _____________.

(x) Amorphous solid has a _____________.

(xi) A p-type semi conductor is electrically _____________.

(xii) The voltage gain of an inverting amplifier is _____________.

(xiii) The momentum of a photon of frequency f is _____________.

(xiv) In Compton scattering the value of Compton’s shift equals Compton’s wave length of electron when X-

ray is scattered at an angle of _____________.

(xv) The value of Rydberg’s constant is _____________.

(xvi) 90 TH 234 decays by emitting a beta particle to form _____________.

(xvii) Which is not the nuclear radiation? _____________.



Q: 2 Write answers of any EIGHT questions. (8x2=16)

(i) Why electric lines of force never cross?

(ii) How can you identify that which plate of a capacitor is positively charged?

(iii) Define electron volt & show that 1 eV= 1.6 x 10-19 J

(iv) Do bend in a wire affect its electrical resistance? Explain.

(v) Is filament resistance lower or higher in a 500 W, 200 V lighted bulb than in a 100 W, 220 V bulb?

(vi) Define resistance and its SI units.

(vii) What should be the orientation of a current carrying coil in a magnetic field so that torque acting upon the

coil is a) maximum b) minimum

(viii) Why the resistance of an ammeter should be very low?

(ix) Define magnetic flux and give its two units.

(x) Four unmarked wires emerge from a transformer. What steps would you take to determine the turns ratio?

(xi) Does the induced emf in a circuit depend on the resistance of the circuit? Does the induced current

depend on the resistance of the circuit?

(xii) In a certain region the earth’s magnetic field points vertically down. When a plane files due north, which

wingtip is positively charged?


(i) Define self inductance and its SI unit.

(ii) How many times per second will an incandescent lamp reach maximum brilliance when connected to a

50 Hz source?

(iii) How the reception of a particular radio station is selected on your radio set?

(iv) Describe four properties of a series resonant circuit.

(v) Explain the electrical behaviour of conductors in terms of energy band theory.

(vi) Differentiate between elastic deformation and plastic deformation.

(vii) Explain what is Curie temperature?

(viii) Find the current gain of a transistor whose collector current is 100 mA and base current is 100 µA.

(ix) How operational amplifier acts as comparator?

(x) Why is base current in a transistor small?

(xi) We cannot observe the Compton Effect with visible light. Why?

(xii) A beam of red light and a beam of blue light have exactly the same energy. Which beam contains the

greatest number of photons?

Q: 4 Write answers of any SIX questions. (6x2=12)

(i) Does time dilation mean that time really passes more slowly in moving system or that it only seems to

pass more slowly?

(ii) The rest mass of a photon is zero. What can you say about its momentum?

(iii) Can electron in ground state of hydrogen atom absorb a photon of 13.6 eV and greater than 13.6 eV?

(iv) Explain why laser action could not occur without population inversion between atomic levels?

(v) Under what conditions Kα & Kβ X-rays are emitted?

(vi) What is the difference in the action of α and β particles for producing ionization?

(vii) What factors make a fusion reaction difficult to achieve?

(viii) What are the particles inside a proton?

(ix) Describe steps of P-P reactions of nuclear fusion in sun.



Q: 5 (a) What is Wheatstone bridge? Explain it with labeled diagram and show how is it used to find the

unknown resistance?

(b) Determine the electric field at a position r ��⃗ =�4i�+ 3j� � m caused by a point charge q = 5.0 x 10-6 C

placed at the origin.

Q: 6 (a) What is motional emf? Derive a relation for it.

(b) How fast must a proton move in a magnetic field of 2.50 x 10-3 T such that the magnetic force is equal

to its weight?

Q: 7 (a) What are energy bands? Differentiate between insulator, and semi conductor on the basis of band

theory of solids.

(b) Find the value of current flowing through a capacitance 0.5 µF when connected to a source of 150 V

at 50 Hz.

Q: 8 (a) Draw the circuit diagram of full wave rectifier. Discuss the working of semi-conductor diode as full

wave rectifier.

(b) What is de-Broglie wave length of an electron whose KE is 120 eV?

Q: 9 (a) What are the basic forces of nature? Also explain the basic building blocks of matter.

(b) Calculate the longest wavelength of radiation in Paschen series.




(i) Value of Rydberg’s constant RH is _____________.

(ii) Thyroid gland plays a major role in distribution of _____________.

(iii) Three up quarks combine to form a new particle, the charge number on this particle is _____________.

(iv) The minimum charge on an object cannot be less than _____________.

(v) If the distance between two charged bodies is halved, the force between them becomes ____________.

(vi) Electromotive force is most closely related to _____________.

(vii) The unit of magnetic flux is _____________.

(viii) To convert galvanometer into ammeter the parallel shunt resistance Rs is equal to

(ix) The principle of AC generator is _____________.

(x) Eddy currents are produced in a material when it is _____________.

(xi) At resonance frequency, the current in RLC series circuit is _____________.

(xii) Magnetism lags behind the magnetizing current, this phenomena is called _____________.

(xiii) Electromagnetic waves emitted from an antenna are _____________.

(xiv) The value of potential barrier for germanium is _____________.

(xv) Photo diode can turn its current on and off in _____________.

(xvi) 0.1 Kg mass will be equivalent to energy _____________.

(xvii) When electron and positron are annihilated, the number of photons produced is _____________.




(i) Define and give the S.l units of electric potential.

(ii) Show that ε and ∆Φ / ∆t have the same units.

(iii) Differentiate between motor and generator.

(iv) Why the resistance of an ammeter should be very low?

(v) How a capacitor is charged and discharged? Draw its R-C circuit.

(vi) Suppose you follow an electric field line due to a positive point charge. Does electric field increase or

decrease? Also what about potential?

(vii) Why the picture on a TV screen does become distorted, when a magnet is brought near the screen?

(viii) How can a current loop be used to determine the presence of a magnetic field in a region of space?

(ix) How can you use a magnetic field to separate isotopes of chemical element?

(x) Does the induced emf always act to decrease the magnetic flux through the circuit?

(xi) Does the induced emf in a circuit depend on the resistance of the circuit? Does the induced current

depend on the resistance of the circuit?

(xii) Electrons always move towards high potential. Explain why?


(i) What is Wheatstone bridge and draw its figure?

(ii) What is meant by AM and FM?

(iii) Why glass is known as solid liquid?

(iv) How can a rheostat be used as potential divider?

(v) Why ordinary silicon dioxide does not emit light?

(vi) Explain briefly the conductors on the basis of energy band theory?

(vii) Explain why the terminal potential difference of a battery decreases when the current drawn from it is

increased?

(viii) Differentiate between ferromagnetic and diamagnetic substances?

(ix) When 10 V are applied to an AC circuit, the current flowing in it is 100 mA. Find its impedance.

(x) How the reception of a particular radio station is selected on your radio set?

(xi) What is the effect of forward and reverse biasing of a diode on the width of depletion region?

(xii) Define input resistance and out-put resistance of an operational amplifier?


(i) Give two postulates of special theory of relativity.

(ii) Define excitation energy and ionization energy.

(iii) What is radioactive tracer?

(iv) What do you mean by critical mass and critical volume?

(v) Give two advantages of laser over ordinary light.

(vi) Describe principle of operation of solid state detector.

(vii) Is it possible to create a single electron from energy? Explain.

(viii) When does light behave as a wave and when does it behave as a particle?

(ix) Protons and neutrons are formed by what types of quarks? Show by diagram.



Q: 5 (a) Define electric potential. Also derive an equation for electric potential at a point due to a point charge.

(b) The potential difference between the terminals of a battery in open circuit is 2.2 V when it is

connected across a resistance of 5.0 Ω. The potential falls to 1.8 V. Calculate the current and the

internal resistance of battery.

Q: 6 (a) Define motional emf and derive a relation for it.

(b) A solenoid 15 cm long has 300 turns of wire. A current of 5 ampere flows through it. What is the

magnitude of magnetic field inside the solenoid?

Q: 7 (a) Describe RLC series AC circuit. Write its properties and find the relation for resonance frequency.

(b) A. 1.25 cm diameter cylinder is subjected to a load of 2500 Kg. Calculate the stress on the bar in

mega pascals.

Q: 8 (a) Write down postulates and results of special theory of relativity. What is NAVSTAR navigation

system?

(b) Calculate the output of the op-amp shown in figure.

Q: 9 (a) Define isotopes. Write a note on mass spectrograph.

(b) Calculate the longest wave length of radiation for Paschen series.

.

+5 V

-2 V

10 kΩ

4 kΩ

20 kΩ

Ground




(i) When a dielectric is placed between two charges then coulomb's force will be _____________.

(ii) A capacitor stores energy in the form _____________.

(iii) Charge carriers in electrolytes are _____________.

(iv) Brightness in cathode ray oscilloscope is controlled by _____________.

(v) The Lenz’s law is in accordance with law of conservation of _____________.

(vi) For step down transformer _____________.

(vii) Energy density in an inductor is _____________.

(viii) Root mean square value of voltage is given by _____________.

(ix) Inductive reactance of an inductor is _____________.

(x) There are different crystal systems. The number of these crystal systems is _____________.

(xi) The potential barrier for silicon is _____________.

(xii) Pulsating output of full wave rectifier can be made smooth by using circuit called _____________.

(xiii) If an object moves with speed of light, its mass will be _____________.

(xiv) Laser is a beam of light which is _____________.

(xv) Speed of the electron in the first Bohr’s orbit is _____________.

(xvi) The particles equal in mass but greater than proton are _____________.

(xvii) At higher energies more than 1.02 MeV the dominant process is _____________.




(i) Show that ε and ∆Φ / ∆t have same units.

(ii) Electric lines of force never cross. Why?

(iii) Write a note on back motor effect in generator.

(iv) Define magnetic flux and its units.

(v) Show that Ohm times Farad is equal to second.

(vi) What is polarization and how dipoles are formed in dielectric?

(vii) Electromagnetic induction is exactly in accordance with the law of conservation of energy. How?

(viii) Why E is zero inside a charged rubber balloon when charge is distributed uniformly over its surface?

(ix) When an electric motor, such as an electric drill is being used, does it also act as a generator? If so what

is the consequence of this?

(x) Is it possible to orient a current loop in a uniform magnetic field such that the loop will not tend to rotate?

Explain.

(xi) Why a voltmeter should have very high resistance?

(xii) Suppose that a charge q is moving in a uniform magnetic field held with a velocity v. Why is there no

work done by the magnetic force that acts on charge q?


(i) Why does resistance of a conductor rise with temperature?

(ii) State Kirchhoff’s rules.

(iii) Write down advantages and disadvantages of AM and FM.

(iv) Distinguish between brittle and ductile substances.

(v) What do you mean by high temperature super conductor?

(vi) Define unit cell and crystal lattice.

(vii) Under what conditions emf of a cell and terminal potential difference become equal?

(viii) Write down two advantages of three-phase AC Supply.

(ix) How does doubling the frequency of AC affect the reactance of: a) An inductor b) A capacitor?

(x) The anode of a diode is 0.2 V positive with respect to its cathode. Is it forward biased?

(xi) What is the effect of forward and reverse biasing of a diode on the width of depletion region?

(xii) What is the net charge on a n- type or a p- type substance? Justify the answer.


(i) What is a radioactive tracer? Describe one application in each case of agriculture and medicine.

(ii) Is it possible to create a single electron from energy? Explain.

(iii) How can the spectrum of hydrogen contain so many lines when hydrogen contains one electron?

(iv) What fraction of a radioactive sample decays after two half lives have elapsed?

(v) If half life of a nucleus is one year, does this mean that it will be completely decayed after two years?

Explain.

(vi) Which has the lower energy quanta? Radio waves or X-rays.

(vii) What do we mean by critical mass?

(viii) Is energy conserved when an atom emits a photon of light?

(ix) Give the two statements of uncertainty principle.



Q: 5 (a) What is meant by electrostatics? Apply electrostatics to explain Xerography.

(b) How many electrons pass through an electric bulb in one minute if 300 mA current is passing

through it?

Q: 6 (a) State and derive Faraday’s law of electromagnetic induction.

(b) Find the radius of an orbit of an electron moving at a rate of 2.0 x 107 ms-1 in a uniform magnetic

field of 1.20 x 10-3 T.

Q: 7 (a) Explain series resonance circuit and give its properties.

(b) What stress would cause a wire to increase the length by 0.01% if the Young’s modulus of the

wire is 1.2 x 1010 Pa. What force would produce this stress if diameter of the wire is 0.56 mm?

Q: 8 (a) State special theory of relativity with two postulates and explain following two results:

(i) Time dilation (ii) Length contraction

(b) In a certain circuit the transistor has a collector current of 10 mA and base current 40 µA. What

is the current gain of the transistor?

Q: 9 (a) Derive the relation for the quantized radii of hydrogen atom on the basis of Bohr’s model of

hydrogen atom.

(b) The half-life of 38 Sr 91 is 9.70 hours. Find its decay constant.

Section-III (Practical)

Q: 10 (A) Answer any FOUR questions from the following. (4x2=8)

(i) Draw the table to find the resistance of wire by “Slide wire Bridge”.

(ii) How the Galvanometer is converted into voltmeter?

(iii) Draw the symbol and truth table of NAND Gate

(iv) Why the V-I graph for a lighted bulb is not a straight line?

(v) How can we test the correctness of connections of “Slide Wire Bridge”?

(vi) Why a diode does not conduct when it is reverse biased?

(vii) In photoelectric effect, by decreasing distance between light bulb and photocell, current increases. Why?

(viii) What are practical uses of potentiometer?

Q: 10 (B) Write down the procedure of any one experiment from following. (3)

(i) To determine the internal resistance of a cell using a potentiometer.

OR

(ii) To study variation of current with the intensity of light in photoelectric effect.

Q: 10 (C) Answer the following questions on the basis of graph drawn below. (4)

Graph is plotted between capacitance and current

(i) What do you conclude from this graph?

(ii) Find the value of capacitance against 12 Ampere.

OR

Graph is plotted between voltage and resistance in case of resistance of voltmeter

(i) Find slope in this graph.

(ii) Find the resistance of voltmeter in this graph.

0, 0

0.1, 5

0.2, 10

0.3, 15

0.4, 20

0.5, 25

0

5

10

15

20

25

0 0.1 0.2 0.3 0.4 0.5

I (

Am

pere

)

C (µF)

GRAPH "A"

-2500, 0

-1500, 0.1

-500, 0.2

500, 0.3

1500, 0.4

2500, 0.5

0

0.1

0.2

0.3

0.4

0.5

-3000 -2000 -1000 0 1000 2000 3000

1 / V

(v

olt

-1)

R (Ω)

GRAPH "B"




(i) The radius of 10th orbit in hydrogen atom is_____________.

(ii) In an electronic transition atom cannot emit _____________.

(iii) The electrostatic force of repulsion between two electrons at a distance 1 m is_____________.

(iv) A charged conductor has charge on its _____________.

(v) Ampere second stands for the unit of _____________.

(vi) The relation between current I and angle of deflection θ in a moving coil galvanometer is _________.

(vii) Lorentz force is given by _____________.

(viii) Which one of the following is not present in an AC generator?

(ix) The core of transformer is laminated or reduces _____________.

(x) In RLC parallel circuit the resonance frequency is _____________.

(xi) Electromagnetic waves emitted from radio antenna are _____________.

(xii) Minority carriers in p-type substances are _____________.

(xiii) The gain of non-inverting amplifier is _____________.

(xiv) The common emitter current amplification factor β is given by _____________.

(xv) In Compton Effect the photon behaves as a _____________.

(xvi) The binding energy per nucleon is maximum for _____________.

(xvii) Gamma rays from Cobalt-60 are used for treatment of _____________.




(i) Show that ε and ∆Φ / ∆t have same units.

(ii) Electric lines of force never cross each other. Why?

(iii) A sensitive galvanometer cannot be stable. Explain?

(iv) Describe five properties electric lines if forces.

(v) Can a step up transformer increases the power level?

(vi) Why is “B'’ non-zero outside a solenoid?

(vii) What is time constant of a capacitor resistance circuit and prove that RC= time constant?

(viii) Why does the picture on a TV screen become distorted when a magnet is brought near screen?

(ix) A plane conducting loop is located in a uniform magnet field that is directed along x-axis. For what

orientation of loop is flux, a maximum? For what orientation is flux, a minimum?

(x) How can you identify that which plate of is a positively charged?

(xi) How would you position a flat loop of wire in a changing magnetic field so that there is no emf induced in

the loop?

(xii) What are similarities between a motor and a generator?


(i) What is choke?

(ii) Write four applications of photodiode.

(iii) Distinguish between crystalline and amorphous solids.

(iv) Write four properties of parallel resonance circuit.

(v) What is meant by strain energy?

(vi) Write a brief note on super conductor.

(vii) Why is the base current in a transistor very small?

(viii) Do bend in a wire affect its electrical resistance? Explain.

(ix) What are the difficulties in testing whether the filament of the lighted bulb obeys Ohm’s law?

(x) How does doubling the frequency affect the reactance of a) an inductor b) a capacitor?

(xi) Why we prefer potential meter in place of voltmeter for measuring potential difference?

(xii) What is the effect of forward and reverse biased of a diode on the width of depletion region?


(i) The rest mass of photon is zero. What can you say about its momentum? Explain briefly.

(ii) What advantages an electron microscope has over the optical microscope?

(iii) What do you understand by background radiation? State two sources of this radiation.

(iv) Protons and neutrons are formed by what type of quarks? Show by diagram.

(v) Can an electron in the ground state of hydrogen atom absorb a photon of energy 13.6 eV or greater than

13.6 eV?

(vi) Find mass “m” of an object moving with speed of 0.8 c.

(vii) Define excitation energy and ionization energy.

(viii) Describe operational principle of solid state detector.

(ix) Define “mass defect” and “binding energy”.



Q: 5 (a) What is electric potential? Find electric potential at a point due to a point charge.

(b) A rectangular bar of iron is 2.0 cm by 2.0 cm in cross section and 40 cm long. Calculate its resistance

if the resistivity of iron is 11 x 10-8 Ωm.

Q: 6 (a) Describe the principle, construction and working of a galvanometer, hence show that the deflection is

directly proportional to current.

(b) A DC operates at 240 V and has a resistance of 0.5 Ω when the motor is running at normal speed the

armature current is 15 A. Find the back emf in the armature.

Q: 7 (a) Describe RLC series circuit. Derive the relation for resonance frequency in this circuit. Also give its

properties.

(b) What stress would causes a wire to increase in length by 0.01% if the Young’s Modulus of the wire is

1.2 x 1010 Pa. What force would produce this stress if diameter of wire is 0.56 mm?

Q: 8 (a) State two postulates of special theory of relativity. Give its three consequences.

(b) In a certain circuit, the transistor has a collector current of 10 mA and a base current of 40 µA. What

is the current gain of transistor?

Q: 9 (a) Derive the expression for radius of orbit and velocity of electron in an orbit on the basis of Bohr’s

atomic model.

(b) A 75 kg person receives a whole body radiation dose of 24 mrad delivered by x-particles for which

RBF factor is 12. Calculate: a) the absorbed energy in joules b) the equivalent does in rem.

Section-III (Practical)

Q: 10 (A) Answer any FOUR questions from the following. (4x2=8)

(i) Draw circuit diagram of slide wire bridge experiment.

(ii) Write down the symbol and Truth table of NAND gate.

(iii) In half deflection method when both keys are closed and shunt resistance is zero. What deflection is

shown by the galvanometer? Why?

(iv) Why the period of flashes increases in Neon flash lamp experiment with the increase in resistance?

(v) When capacitors are connected in parallel whether their capacitance is increased or decreased? Explain.

(vi) How would you convert galvanometer into a voltmeter?

(vii) In photoelectric effect, by decreasing distance between light bulb and photocell, current increases. Why?

(viii) Why we connect the voltmeter parallel to measure the potential difference across two points in a circuit?

Q: 10 (B) Write down the procedure of any one experiment from following. (3)

(i) To determine the resistance of a galvanometer by half deflection method.

OR

(ii) To prove that photoelectric current is proportional to the intensity of light.

Q: 10 (C) Answer the following questions on the basis of graph drawn below. (4)

Graph is plotted between R-S and R x S

(i) Find the slope of graph.

(ii) Which quantity is represented by the slope of graph? Give its unit.

OR

Graph is plotted between resistance and time period of flashes of Neon Flash lamp

(i) What you conclude from the graph?

(ii) Find time period for resistance 3.5 kΩ.

4000,0.0041

4400,0.0045

4800,0.0049

5200,0.0053

5600,0.0057

0.0041

0.0045

0.0049

0.0053

0.0057

4000 4500 5000 5500

R x

S (

Ω2)

R - S (Ω)

GRAPH "A"

1, 2

2, 4

3, 6

4, 8

5, 10

6, 12

2

4

6

8

10

12

1 2 3 4 5 6

T (

sec)

R (kΩ)

GRAPH "B"

AAnnsswweerr KKeeyy OObbjjeeccttiivvee

2006 2007 Question 7 Question 7

(i) Intersect each other (i) N m2 C-2

(ii) Non-Ohmic Device (ii) E2 / 4R

(iii) Tesla (iii) Circular path

(iv) Energy (iv) Ns > Np

(v) Large (v) X = A+B��

(vi) A missing Electron (vi) Interference

(vii) AC into DC (vii) nh / 2π

(viii) Annihilation of Matter (viii) 1 J kg-1

(ix) Ground State (ix) π/2

(x) Baryons (x) 750 °C

Question 8 Question 8

(i) Energy (i) Shape or Geometry

(ii) Decimal Multiplier (gives number of Zeros) (ii) Non-Ohmic

(iii) Magnetic force (iii) Lorentz

(iv) Primary (iv) Zero

(v) Capacitor (v) Peak Value

(vi) Ductile Substance (vi) No units

(vii) Switch (vii) Logic Gates

(viii) Greater (viii) Specimen

(ix) De-acceleration (ix) 85%

(x) Electrons (x) Fast

2008 2009 (i) Coulomb (i) N-1 m-2 C2

(ii) Millikan (ii) 1.6 x 10-19 electrons

(iii) Kilowatt Hour (iii) Charge

(iv) 0.5 A (iv) V = IR

(v) In the direction perpendicular to field and its motion

(v) Magnetic Field

(vi) weber (vi) All of these

(vii) ohm (vii) Inductance

(viii) Equal to its resistance (viii) 1 Ohm x 1 Sec

(ix) Brittle substances (ix) Magnetic Effect

(x) Amplifier (x) Np > Ns

(xi) All of these (xi) Io / √2

(xii) Long wavelength (xii) 0°

(xiii) 1600 °C (xiii) Conductor

(xiv) 10-10 m (xiv) Decreases

(xv) γ-rays (xv) m = hf / c2

(xvi) Iodine-131 (xvi) All of these

(xvii) γ-rays (xvii) Photon

2010 2011 (i) Angular momentum (i) 1.02 MeV

(ii) 15% (ii) Cadmium rods

(iii) 10-8 sec (iii) Germanium

(iv) Atomic Number (iv) Zigzag or erratic path

(v) Positively Charged particles (v) ohm

(vi) Modulation (vi) Work function

(vii) Insulator (vii) Maximum

(viii) Less than forward current (viii) 1.6 x 10-19 J

(ix) Einstein (ix) 5

(x) K = c / NAB (x) Photoelectric Effect

(xi) τ = NIAB cosα (xi) nh / 2π

(xii) Ns > Np (xii) A good conductor

(xiii) Transformer (xiii) Made small

(xiv) Electric intensity (xiv) Controls the brightness of spot formed

(xv) C = Aεo / d (xv) ½ B2 / µo

(xvi) Resistor (xvi) IC / IB

(xvii) ± 10% (xvii) Increased

2012 2013 (i) 1.6 x 10-19 C (i) 1.0974 x 107 m-1

(ii) Volt (ii) Iodine

(iii) Resistance is doubled (iii) 2

(iv) Magnetic Field (iv) 1.6 x 10-19 C

(v) F = qvB sinθ (v) Four times

(vi) Rs = IgRg / I - Ig (vi) Potential difference

(vii) Mutual Inductance (vii) weber

(viii) Um = ½ LI2 (viii) Rs = IgRg / I - Ig

(ix) Xc = 1 / 2πfC (ix) Electromagnetic Induction

(x) Disordered structure (x) Placed in time varying magnetic field

(xi) Neutral (xi) Maximum

(xii) -R2 / R1 (xii) Hysteresis

(xiii) hf / c (xiii) Transverse

(xiv) 90° (xiv) 0.3 V

(xv) 1.0974 x 107 m-1 (xv) Nano-sec

(xvi) 91 Pa 234 (xvi) 9 x 105 J

(xvii) X-rays (xvii) 2

2014 2015 (i) Decreased (i) 5.3 nm

(ii) Electrical energy (ii) γ-radiations

(iii) Positive and Negative ions (iii) 2.3 x 10-30 N

(iv) Grid (iv) Outer surface

(v) Energy (v) Charge

(vi) Np > Ns (vi) I α θ

(vii) Directly proportional to B2 (vii) F ��⃗ =q E ��⃗ + q( V ��⃗ × B ��⃗ ).

(viii) Vrms = Vo / √2 (viii) Commutator

(ix) XL = 2 πfL (ix) Eddy Current Loss

(x) 7 (x) 1 / 2π√LC

(xi) 0.7 V (xi) Transverse

(xii) Filter (xii) Electrons

(xiii) Infinity (xiii) 1 + R2 / R1

(xiv) Monochromatic (xiv) IC / IB

(xv) 2.19 x 106 ms-1 (xv) Particle

(xvi) Baryons (xvi) Iron

(xvii) Pair production (xvii) Cancer

bise rawalpindi past paper _2nd year_ physics 2006-2015

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