physics discussion questions

1 | End of Year Physics Review Questions, 2014

ST. DENIS SSEBUGWAWAO SS GGABA

Uganda Certificate of Education, 2014

End of Year Review Questions

Attempt all questions carefully and systematically

1. (a) State Newtons laws of motion

(b) (i) Distinguish between scalar and vector quantities.

(ii) Give two example of each quantity mentioned in (b) (i) above.

(c) Explain why passengers in a vehicle need to fasten their seat-belts.

(d) Distinguish between elastic and perfectly inelastic collisions.

(e) (i) state the law of conservation of linear momentum

(ii) A car of mass 1200kg moving with velocity of 60ms-1

collides

head on with another car of mass 1000kg at rest and they stick

together. Calculate their velocity after collision.

(f) (i) The figure below shows a block of mass 0.5 pulled from rest on

a frictionless table by a steady force F and attained a speed of

8 1 in 2s. Find the force .

. kg0 5

F

(ii) Four forces of 2 N, 5 N, 10 N and 20 N act on a doll as shown in

the figure below. Find the magnitude of the resultant force acting

on the doll.

N5

N10

N20

N2

Object

(g) (i) What is friction?

(ii) State two advantages and two disadvantages of friction

(ii) Sate two ways of reducing friction

2. (a) Define the following terms

(i) displacement;

(ii) velocity;


(iii) uniform velocity;

(iv) acceleration;

(v) uniform acceleration

(b) The following diagram shows the distance time graph for a dog walking

along a pavement.

B

D

A

C

E

0 2 4 6 8 10 12 14 Time (s)

Distance (m)

20

10

F G

(i) Describe the motion of the dog between; A and B; B and C; C and

D; D and E; E and F; F and G.

(ii) What is the velocity of the dog between D and E?

(iii) What is the velocity of the dog between E and F?

(c) A car travelling with a uniform velocity of 25ms-1

for 5s brakes and then

comes to rest under a uniform deceleration in 8s.

(i) Sketch a velocity time graph of the motion

(ii) Find the total distance travelled

(d) A stone of mass 100g is thrown vertically upwards with a force of 5N.

What is its initial acceleration? ( =10ms-2)

3. (a) (i) Define pressure

(ii) State the principle of transmission of pressure in liquids.

(iii) Give four practical applications of pressure in liquids and gases

(b) (i) write down the formulae for calculating in a liquid

(ii) State the factors on which pressure in a liquid depends

(iii) Describe a simple experiment to show that pressure in liquids

increases with depth.

(c) the figure below shows a hydraulic lift raising a 2000 kg automobile when

a 500 N force is applied to the smaller piston. If the smaller piston has an

area of 10 cm2, what is the cross-sectional area of the larger piston?


(d) State the following

(i) Archimedes principle

(ii) The law of floatation

(e) What is buoyant force?

(f) A basketball floats in a bathtub of water. The ball has a mass of 0.5 kg and

a diameter of 22 cm. Given that the density of water is 1000kgm-3

.

(i) What is the buoyant force?

(ii) What is the volume of water displaced by the ball?

(iii) What is the average density of the basketball?

(g) Explain why a ship is able to float in water inspite of being made out of

steel.


(i) stress

(ii) strain

(b) (i) State Hookes law

(ii) With the aid of a labeled diagram, describe a simple experiment to

verify Hookes law using a spring.

(c) A spring has an original, unloaded length of 25 mm. When a load of 2N is

applied the length becomes 29mm.

(i) Calculate the extension for 2N.

(ii) Calculate the extension for 5N.

(iii) Calculate the new length when 5N is added to the spring

(d) What is meant by the following?

(i) elastic material

(ii) proportional limit

(e) A substance suspended from a spring produces an extension of 10cm.

when 600g is suspended on the spring, it produces an extension of 4cm.

Find the mass of the substance.

(f) A steel rod of cross-sectional area 32 m2 is 4m long. When a force of 1.6 x

105 N is applied to the rod, its length increased by 1 mm. Calculate the;

(i) stress in the rod,

(ii) strain produced



(i) conduction

(ii) convection

(iii) radiation

(b) (i) draw a well labeled diagram of a thermos flask

(ii) Briefly explain how the thermos flask work

(c) (i) State Boyles law

(ii) With the aid a labeled diagram, describe an experiment to verify

Boyles law

(d) An ideal gas is contained in a metal cylinder with a volume of 0.25 m3 at a

pressure of 15 x 105 Pa and a temperature of 20C. If the gas is allowed to

expand into the atmosphere at a pressure of 105 Pa and a temperature of 15

C, what is its new volume?

(e) (i) Give two reasons why water is not suitable as a thermometric

liquid.

(ii) State to advantages and two disadvantages of mercury over ethanol

as a thermometric liquid.

(f) During the construction of a rail way line, the rails are sometimes

stretched slightly then welded together end to end when under tension.

Explain why the rails should be stretched.

(h) Give any three application of expansion in daily life.

6. (a) (i) What is meant by refraction of light?

(ii) State the laws of refraction of light.

(b) With the aid of a labeled diagram, describe an experiment to determine the

refractive index of a material of a glass block.

(c) (i) With the aid of a labeled diagram, describe the structure and

working of a simple lens camera.

(ii) State two differences and two similarities between the human eye

and the lens camera

(d) (i) Define critical angle and total internal refection.

(ii) State the conditions under which total internal reflection occurs.

(iii) The critical angle of diamond is 24.4. Calculate its refractive

index.

(f) (i) Explain dispersion as applied to light.

(ii) What is a pure spectrum? Give an example of a pure spectrum.

(iii) With the aid of a labeled diagram, describe briefly how a pure

spectrum is produced.

(iv) Distinguish between a primary and a secondary colour. Mention

one primary and one secondary colour you know.


(g) The fig. below shows colours mixed by addition. Name the colours

represented by the parts labeled A, B, C and D.

Red

C

Green

Blue

B

A

D

7. (a) Define the following as applied to wave motions:

(i) frequency

(ii) wave length

(b) With two examples each, explain using diagrams, the difference between

transverse waves and longitudinal waves.

(c) A radio station transmits signals at a frequency of 103.7MHz. Find the

wave length of the signals and state any assumptions made.

(d) Draw a diagram to show the pattern for a straight water wave passing

through a narrow slit.

(e) Describe an experiment to demonstrate that sound waves require a

material medium for their propagation.

(f) Explain how sound waves travel through air.

8. (a) (i) Define an echo.

(ii) Briefly describe the conditions under which echoes are formed.

(iii) List any two applications of echo in everyday life.

(b) Describe an experiment to determine the speed of sound in air by echo

method.

(d) A child stands between two cliffs and makes a loud sound. If it hears the

first echo after 1.5 s and the second echo after 2.0 s, find the distance

between the two cliffs. (Speed of sound in air =3201).

(e) State any three

(i) differences between sound waves and light waves.

(ii) similarities between sound waves and light waves.

(iii) examples which confirm that light travels faster than sound.

9. (a) State the laws of electrostatics

(b) Explain with the aid of diagrams how to charge two spheres by induction

using a positively charged rod


(c) (i) What is meant by an electric field

(ii) Draw a diagram to show the electric field between two oppositely

charged parallel metal plates

(d) (i) Draw a labeled diagram of a gold leaf electroscope

(ii) Explain how a charged gold leaf could be used to determine if the

charged body had a charge of the same sign

(e) Describe the action of a lightening conductor.

(f) What is meant by a conductor and an insulator? Give two examples of

each.

10. (a) (i) State Ohms law.

(ii) Sketch the characteristics of an Ohmic and non-Ohmic

conductors.

(iii) Describe with the help of a suitable diagram how you can verify

Ohms law

(b) Four resistors are connected across a 12V battery, of negligible internal

resistance as shown in the figure below.

3

3

2

4

V12

A

(i) Determine the reading of the ammeter, A

(ii) the p.d across the parallel combination of resistors.

(c) (i) Distinguish between a primary cell and a secondary cell.

(ii) Mention four ways of caring and maintaining a secondary cell.

(d) Draw a well labeled diagram of a dry (Leclanche) cell.

(e) How is polarization overcome in a dry cell?

11. (a) (i) What is a transformer?

(b) (i) Figure below shows a step-down transformer. Name the coils

marked A and B.


AV480 V24B outputInput

(ii) If the transformer is used to step down mains supply from 480V to

24V and coil A has 800 turns, determine the number of turns in

coil B.

(iii) State two ways by which energy losses in a transformer are

minimized.

(c) Give one advantage of a.c. over d.c.

12. (a) What are X-rays?

(b) With the aid of a labeled diagram, describe the structure and operation of

an X-ray tube

(c) Explain briefly how each of the following can be increased in an x-ray

tube;

(i) Intensity of X-rays

(ii) penetrating power of X-rays

(d) What are the differences between hard and soft X-rays?

(e) (i) State four ways in which X-rays are similar to gamma rays.

(ii) State two ways in which X-rays are different from gamma rays.

(iii) Give two biological and two industrial uses of X-rays

(f) Radon, 86222 decays to radium isotope, Ra, by emission of two beta

particles according to the following equation.

86222 + 2 1

088

(i) What is the value of A?

(ii) How many neutrons does the nucleus of radium isotope have?

(g) What is meant by:

(i) Mass number?

(ii) Name any two radiations emitted by radioactive substances.

(iii) In the nuclear equation given below, find the values of .

+ 01

92235 92

236 + 36

144 + 2 + 0

1

(h) (i) What is the difference between nuclear fission and nuclear fusion?

(ii) Give one method of starting the process in nuclear fission.

(iii) State one use of nuclear energy.

13. (a) (i) What is meant by cathode rays?

(ii) With the aid of a labeled diagram, describe how cathode rays are

produced by thermionic emission.


(b) (a) What is meant by

(i) half life

(ii) radio activity

(c) What happens to the activity of a radioactive material when its

(i) mass is increased

(ii) temperature is increased

(d) A material is wrapped in photo graphic film and kept in a dark room.

When the photographic film is removed, it is found to be darkened.

(i) identify the material

(ii) explain the observation

(e) A radioactive substance of mass 60g takes 400years for its mass to be

reduced to 15g. Find its half life.

(f) State:

(i) two industrial and two medical uses of radioactivity

(ii) two health hazards of radioactivity

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