RAVI AGARWAL (M.SC.)- 9913650950 / 9374727052

TIME: 3 Hrs. CH. Full Course MARKS: 80

Q.I Questions numbers 1 to 30 are objectives, carrying ONE mark each. (30) 1. 1 amu = _____ Kg.

a) 1.6 × 10-27 b) 1.6 × 10-19 c) 9.1 × 10-31 d) 6.02× 1023

2. The ________ force is the force of mutual attraction between any two objects by virtue of their masses. (a) Weak nuclear (b) Electromagnetic (c) Nuclear (d) Gravitation

3. S2 = at4. Here S is measured in meters, t in second. Then the unit of ‘a” is: (a) m2s4 (b) m2s-4 (c) ms2 (d) ms-2

4. 2N,2N,4N and 4N forces acting on the body in the direction of North, South, East and West respectively. Under the effect of above forces body is in ______. (a) accelerated motion (b) equilibrium (c) circular motion (d) uniform velocity 5 The time derivative momentum gives _____ (a) force (b) velocity (c) negative of force (d) acceleration 6 The source of gravitational field is _______ (a) stationary charge (b) mass (c) moving mass (d) moving charge 7 A spring of force constant k is stretched so that its length becomes double. Its force constant will be ____.

(a) k2

(b) 2k (c) 4k (d) k

8 Period of a simple pendulum, suspended from the roof of a coach of a train, is T, when the train is not moving. Now the train starts its accelerated motion. Period of the pendulum will _____. (a) increase (b) decrease (c) not change (d) become infinite 9 What is Heat conduction? 10 Write the differential equal of forced oscillation? 11 What was the law of cooling given by Langmuir-Lorentz? 12 What is meant by ‘Normal modes of Oscillation’? 13 Define: Surface Tension w.r.t Potential energy 14 What is Avagadro’s hypothesis? 15 What are the units of Thermal Conductivity and Resistivity? 16 What is astrophysics? 17 What is to be done to fully describe events occurring in our surrounding? 18 When a body is said to be in motion? 19 A screw gauge and a spherometer can be used to measure length down to ____ m. 20 What is concurrent force? 21 “The gravitational acceleration produced in heavy body is greater than that of light body.”- Check the validity of the statement. 22 What is the stopping distance of vehicle? 23 Give Torricelli’s law 24 What do you mean by ‘polar satellite’? 25 What was the contribution of Ptolemy? 26 Give statement of perpendicular axis theorem regarding motion of inertia. 27 Write CGS and MKS units of force constant and write relation between them. 28 Due to what elasticity of materials depend? 29 Plot the graph of amplitude versus time for a forced oscillation. 30 A wire of length L and radius r is having Young modulus Y. What will be the new Young modulus if the length and radius is reduced by half?

Q.III Question number 31 to 40 are short answer questions, each carries TWO marks (20) 31 Describe the method for the measurements of distance between Sun and Earth and also the distance between planet and Sun. 32 Pressure (P) acting on the base of fluid (gas or liquid) of column of height (h) depends on height, density (ρ) of fluid and gravitational acceleration (g). From this fact, obtain an equation of pressure using the method of dimensional analysis. 33 How a unit of a physical quantity should be?34 Derive the expression for maximum safe speed of a vehicle Vmax on a balanced road.35 State the formula for the work done by variable force on a particle moving on curved path. If force remains constant along this path then calculate the work done.36 With the help of diagram explain Uniform Circular motion.

37 What is V rms? Write its different expressions on the basis of kinetic theory of gases where, P =

pressure, T = absolute temperature. σ = density, M 0 = molecular weight of gas. R = Gas constant,

K = Boltzmann constant, m = mass of molecule.

38 Derive the differential equation for damped oscillations and state its solution. Will there be

oscillations, if km

= ( b2m )2?

39 Derive the expression for elastic potential energy of spring.40 Using dimensional analysis, obtain the speed of transverse waves in a medium like a string kept under tension.

Q.IV Question number 41 to 50 are short answer question each carries THREE marks (30) 41 An object is allowed to fall freely from a distance r from the centre of the earth. Calculate the speed of the object when it strikes the surface of the earth. 42 The pressure at certain depth in a sea is 80 atm. If the density of water at the surface of the sea is 1.03 ×103 kg/m3 and the compressibility of water is 45.8 ×10-11 Pa-1, calculate the density of

water at the mentioned depth. [1atm = 1.013 ×105 Pa.]

43 What should be the lengths of a brass and an aluminium rod at 0℃, if the differences between their lengths are to be maintained equal to 5 cm at any temperature? (For brass α = 18 × 10-6℃-1 and for aluminium ∝ = 24 × 10-6 ℃-1.) 44 A stationary bomb explodes into 3 fragements. Two of these fragements are of equal mass and they fly off along mutually perpendicular directions with equal velocity of 30 m/s. The third fragement is 3 times heavier than each one of the other two. Find the magnitude and direction of the third one? 45 Show that r1

=r [ m 2m2+m 1 ] and r2 =r [ m 1

m2+m 1 ], when the distance between two particle of masses m1 & m2

is r. If the distance of these particles from the C.M. of the system are r1 and r2 respectively. 46 Prove that work done by an ideal gas during an adiabatic process in which it goes from initial state ( P1, V1, T1) to the final state (P2, V2, T2) is given by W = P1V1-P2V2 = μr(T1-T2) . γ-1 γ-1 47 A metal rod of 1m length is in a steady thermal state at atmospheric pressure. Its one end is placed in water at 100℃ and the other end is placed in ice at 0℃. At what distance from its hot end a flame of temperature 2000℃ should be placed so that per unit time, the same amount of water evaporates at the hot end as the amount of ice melts at the cold end? Latent heat of evaporation of water = 560 cal/gm. Latent heat of vapourisation = 80cal/gm. 48 If the radius of the Earth suddenly drop to 60 % of the present value, the mass of the Earth remaining the same, what will be the change (in percentage) in the magnitude of gravitational acceleration on the surface of the Earth? 49 A pendulum clock having a period of 2 s on the earth is taken to the moon. Will it run faster or slower? How much time will it gain or lose in 1 hr? Tak e ge = 10 m/s2 and gm = 02 m/s2. 50 A copper wire is held at both ends by rigid supports. At 30℃ it is just taut with negligible tension. Find the speed of transverse waves in it at 0℃. For Copper, coefficient of linear expansion α = 1.7 × 10-5℃-1. Young modulus Y = 1.3 × 1011 N/m2 and density ρ = 9× 103 kg/m3.

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