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S.3 Physics Lira Town College

LIRA TOWN COLLEGE

S.3 MID - TERM II EXAMS 2013  PHYSICS    TIME:         2 HOURS

Instruction:   

Attempt all questions in both sections A and B.

SECTION A

1. An object is placed 6cm from a plane mirror.  If the object is moved further by 2cm, find the distance between the object and its image.

  1. 16cm
  2. 12cm
  3. 8cm
  4. 6cm

2. The energy transformations involved in a bicycle dynamo is

  1. Electrical to chemical
  2. Potential energy to chemical energy
  3. Chemical to light energy
  4. Kinetic to electrical energy

3. A driver uses a convex mirror as his driving mirror because it

                (i)  Forms an upright image

                (ii)  Gives a bigger magnification

                (iii)  Gives a wider field of view

  1. (i) only
  2. (i) and (ii) only
  3. (iii) only
  4. All the above

4. Which of the following statements about eclipse is not correct?

  1. During the eclipse of the sun, the shadow of the moon falls on the earth
  2. During the eclipse of the moon, the earth is between the sun and the moon
  3. During the eclipse of the sun, the moon is between the sun and the earth
  4. During the eclipse of the moon, the shadow of the moon falls on the earth

5. Which one of the following gives a defect and its correction in a simple cell?

 

Defect

Correction

A

Local action

Use zinc amalgam

B

Polarization

Dilute the electrolyte

C

Local action

Add oxidizing agent

D

Polarization

Use concentrated electrolyte

6. Parallel rays can be obtained practically from a point source of light if the source is placed at

  1. The principal focus of a concave reflector (mirror)
  2. The centre of curvature of a concave reflector
  3. The principal focus of a convex reflector
  4. The centre of curvature of a convex reflector

7.  The diagram in Fig. above illustrates an experiment to determine the refractive index of glass.  Which one of the following graphs would give a straight line through the origin?

  1. against
  2. Sin i against r
  3. Sin r against i
  4. I against r

8. The brightness of the image formed by a pin-hole camera depends on

  1. The size of the object
  2. The shape of the object
  3. The size of the pin-hole
  4. The shape of the pin-hole

9. Which one of the following cannot generate e.m.f?

  1. Magnetization
  2. Chemical reaction
  3. Electromagnetic induction
  4. The piezo electrical effect

10. The refractive index of glass is 1.5.  Calculate the angle of refraction for light incident on glass at an angle of 30o.

  1. 19.5o
  2. 42.0o
  3. 45.0o
  4. 48.6o

11. A current of 5A flows through a given point in a circuit for 120 seconds.  Calculate the quantity of charge that passes the point.

  1. 2.5c
  2. 10c
  3. 300c
  4. 600c

12. Which of the following statements is/are true about molecular theory of magnetism?

                (1)          Breaking a magnet into two results into the formation of two magnets

                (2)          Heating and rough treatment destroys magnetism

                (3)          The poles of a magnet are of equal strength

                (4)          The lines of force travel from a north pole towards a south pole.

  1. 1, 2, 3 only are correct
  2. 1, 3 only are correct
  3. 2, 4 only are correct
  4. 4 only is correct

13. A thermo couple is an instrument which converts

  1. Heat energy to electrical energy
  2. Electrical energy to light energy
  3. Light energy to electrical energy
  4. Chemical energy to heat energy

14. Permanent magnets are made from

  1. Diamagnetic materials
  2. Ferromagnetic materials
  3. Paramagnetic materials
  4. Dielectric materials

15. Which of the following statements are true about magnets?

                (1)          Magnets always have opposite pobrities

                (2)          A magnet can be used as a compass

                (3)          Repulsion is the only sure test for a magnet

                (4)          Magnets attract all metals

  1. 1, 2, 3 only are correct
  2. 1, 3 only correct
  3. 2, 4 only correct
  4. 4 only correct

16.  In a simple cell

  1. Polarization is caused by impure zinc
  2. Potassium dichromate is used to prevent polarization
  3. The formation of hydrogen bubbles on the copper plate causes local action
  4. Hydrogen is produced on the zinc plate and causes polarization

17. In which of the following devices is kinetic energy converted to electrical energy?

  1. An accumulator
  2. A dynamo
  3. An electric motor
  4. A combustion engine

18. Which of the following statements are correct?

        (1)  The particles of magnetic materials are tiny magnets

         (2)   The particles in un magnetized iron arrange themselves in closed chairs

         (3)   The particles in a magnet are arranged in open chairs with N – pole of one particle

Against the S – pole of its neighbouring particle.

          (4)    Groups of atoms form a magnetic domain.

  1. 1, 2 and 3 only
  2. 1, 2 and 4 only
  3. 2 and 4 only
  4. 4 only

19.  A stick with one end immersed in water appears bent at the water surface because of

  1. Diffraction
  2. Reflection
  3. Interference
  4. Refraction

20.  The forces which hold the molecules in a water drop together are called

  1. Surface tension
  2. Adhesive force
  3. Cohesive forces
  4. Electrostatic force

21.  A sea breeze occurs

  1. When cool air blows towards the land
  2. When warm air blows towards the land
  3. During the night
  4. When cool air blow towards the sea

22. Which of the following statements is true of a wedge used as a simple machine?

  1. Very small force is used to lift a big load
  2. Work done is always so much
  3. Effort on the wedge is applied vertically
  4. There is no frictional force

23. A rectangular block of dimension 4m x 2m x 1m rest on the table with a mass of 50kg.  Calculate the maximum pressure can be exerted on the table in N/m2

  1. 800
  2. 840
  3. 850
  4. 900

24. A liquid of volume 0.4m3 and density 900kg/m3 is mixed with liquid Z of volume 0.15m3 and density 800kg/m3.  Calculate the density of the mixture in kg/m3

  1. 800
  2. 840
  3. 850
  4. 900

25. A force of 10N acts on a body and produces an acceleration of 2m/s2.  The mass of the body is

  1. 0.2kg
  2. 6.0kg
  3. 20kg
  4. 50kg

26.     A ball of 1kg falls from the height of 5m.  Find the kinetic energy.

  1. 5J
  2. 20J
  3. 30J
  4. 50J

27.  A boy pulls a block of wood with a force of 30N through a distance of 300m in 2 minutes.  Find the power developed.

28.  Which of the following changes occurs when a metal block is heated?

           Volume                                           Mass                                           Density

  1. Increases                                    remain the same                           decreases
  2. Increases                                     increases                                      increases
  3. Remain the same                    remain the same                              decreases
  4. Increases                                 remain the same                              increases

29.  A tank 2m tall and base area 2.5m2 is filled with a liquid which exerts a force of 40000 at the bottom.  Calculate the density of the liquid.          

30. In order to make a mercury thermometer more sensitive the

  1. Degree marking must be further apart
  2. Diameter of the capillarity tube must be reduced
  3. Volume of the mercury bulb must be reduced
  4. Capillary tube must be open to air

31. The temperature at which all the heat energy is removed from a substance is called

 

  1. Kelvin temperature
  2. Celsius temperature
  3. Freezing temperature
  4. Absolute dew temperature

32. Which of the following physical properties changes when the body is moved from earth to moon?

  1. Mass
  2. Volume
  3. Weight
  4. Density

33.  A dull black surface feels hotter even though it is at the same temperature as a shiny surface because it

  1. Has more heat than shiny surface
  2. Emits more heat than shiny surface
  3. Reflect heat than shiny surface
  4. Conduct more heat than shiny surface

34.  A bullet of mass 0.12kg is fired with a speed of 40m/s.  Calculate the kinetic energy.

  1. 0.4J
  2. 0.8J
  3. 16J
  4. 32J

35. Which of the following are brittle substances?

  1. Leather, glass, wood
  2. Clay, cast iron, stone
  3. Glass, cast iron, stone
  4. Rubber, polyester, copper wire

37. A needle may float on a clean water, but sinks when detergent is added to water because the detergent

  1. Reduces the density of water
  2. Increases the surface tension of water
  3. Lower surface tension of water
  4. Lower the volume of water

38. The particle in a solid at room temperature are: -

  1. Close together and vibrating
  2. Close together and stationary
  3. Far apart and moving randomly
  4. Close together and moving randomly    

                                                                                  SECTION B      (60 MARKS)

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

                                                …………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………

                                (ii)           State the laws of refraction.

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                                                …………………………………………………………………………………………………………………………….

 

                (b)          (i)            Define absolute refractive index.

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                                                …………………………………………………………………………………………………………………………….

(ii)           The refractive index of water is 4/3.  Find the refractive index of a ray passing from water to air.

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                                                …………………………………………………………………………………………………………………………….

42.          (a)          What is meant by rectilinear propagation of light?

                                …………………………………………………………………………………………………………………………………………

                                …………………………………………………………………………………………………………………………………………

                                …………………………………………………………………………………………………………………………………………

(b) An opaque object is placed infront of a source of light.  Draw ray diagrams to show the formation of a shadow when

                (i)            a point source is used.

 

 

                (ii)           an extended source is used.

 

 

 

 

 

43.          (a)          State the laws of reflection of light.

                                (i)            …………………………………………………………………………………………………………………………….

                                                ……………………………………………………………………………………………………………………………

 

                                (ii)           ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

 

                (b)          (i)            Distinguish between regular and diffuse reflection of light.

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                                                …………………………………………………………………………………………………………………………….

 

                                (ii)           Mention any two uses of plane mirrors.

  1. …………………………………………………………………………………………………………………………….…………………………………………………………………………………………………

 

  1. ……………………………………………………………………………………………………………….

                                                ……………………………………………………………………………………………………………….

44.          (a)          (i)            Why is a dry cell called a primary cell?

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

 

                                (ii)           What is local action in a simple cell?

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

 

                (b)          Draw a diagram to show the structure of a simple cell.

 

 

 

 

45.          (a)          State two advantages of a nickel iron accumulator over lead-acid accumulator.

                                …………………………………………………………………………………………………………………………………………

                                …………………………………………………………………………………………………………………………………………

                (b)          Name the gases evolved during the charging of a lead acid accumulator.

                                …………………………………………………………………………………………………………………………………………

                                …………………………………………………………………………………………………………………………………………

                (c)           List three precautions necessary to prolong the life of a lead acid accumulator.

                                (i)            …………………………………………………………………………………………………………………………….

                                                ……………………………………………………………………………………………………………………………

                                (ii)           ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                                (iii)          …………………………………………………………………………………………………………………………….

                                                …………………………………………………………………………………………………………………………….

46.          (a)          What is meant by: -

                                (i)            Magnetic saturation?

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                                (ii)           Neutral point in a magnetic field.

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                (b)          (i)            State the difference between the magnetic properties of iron and steel?

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                                (ii)           Draw a magnetic field line of a repelling magnet.

 

 

 

 

 

47.          (a)          Define the term velocity ratio.

                                …………………………………………………………………………………………………………………………………………

                                …………………………………………………………………………………………………………………………………………

 

(b)          A wheel and axel machine has efficiency of 45%.  If the radii of the wheel and axle are 20mm and 2mm respectively, find

                (i)            Velocity ratio

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                                (ii)           Mechanical advantage

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

48.          (a)          What is meant by the following: -

                                (i)            an elastic material

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

                         (ii)           Proportional limit.

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

            (b)    A substance suspended from a spring produces an extension of 4cm.  Find the mass of the body.

………………………………………………………………………………………………………………………………

                                …………………………………………………………………………………………………………………………………………

                                …………………………………………………………………………………………………………………………………………

                                …………………………………………………………………………………………………………………………………………

 

49.          (a)          State what is observed in a smoke cell when studying Brownian motion.

                                …………………………………………………………………………………………………………………………………………

                                …………………………………………………………………………………………………………………………………………

 

                (b)          Explain what would be observed when the temperature of the smoke cell is reduced.

                                …………………………………………………………………………………………………………………………………………

                                …………………………………………………………………………………………………………………………………………

 

50.          (a)          Define work.

                                …………………………………………………………………………………………………………………………………………

                                …………………………………………………………………………………………………………………………………………

 

(b)          A body is raised above the ground to the height of 20m.  It is then released, if the mass of the body is 30kg

                (i)            State the energy charges that occurred.

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

 

                                (ii)           Kinetic energy

                                                ……………………………………………………………………………………………………………………………

                                                …………………………………………………………………………………………………………………………….

“NO PAINS NO GAINS”        

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