## Study Questions

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##### PHYSICS (2013) QUIZ STUDY
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.

1.

A piece of radioactive material contains 1000 atoms. If its half-life is 20 seconds, the time taken for 125 atoms to remain is

.
A.

20 seconds

B.

40 seconds

C.

60 seconds

D.

80 seconds

2.
When a brick is taken from the earth's surface go the moon, its mass
.
A. remains constant
B. reduces
C. increases
D. becomes zero.

3.

The resultant of two forces is 50N. If the forces are perpendicular to each other and one of them makes an angle of 30º with the resultant, find its magnitude.

.
A.

100.0N

B.

57.7N

C.

43.3N

D.

25.0N.

4.
The pair of physical quantities that are scalar only are
.
A. volume and area
B. moment and momentum
C. length and displacement
D. impulse and time.

5.
A simple pendulum of length 0.4m has a period of 2s. What is the period a similar pendulum of length 0.8m at the same place?
.
A. 8s
B. 4s
C. 2J2s
D. J2s.

6.

A train with an initial velocity of 20ms-1 is subjected to a uniform deceleration of 2m-2. The time required to bring the train to a complete halt is

.
A.

5s

B.

10s

C.

20s

D.

40s.

7.

Calculate the apparent weight loss of man weighing 70kg in an elevator moving downwards with an acceleration of 1.5ms-2.

[g = 10ms-2]

.
A.

686N

B.

595N

C.

581N

D.

105N.

8.

A piece of cork floats in a liquid. What fraction of its volume will be immersed in the liquid?

[density of the cork = 0.25 x 103kg-3, density of the liquid = 1.25 x 103kgm-3]

.
A.

0.8

B.

0.5

C.

0.2

D.

0.1

9.

An object is moving with a velocity of 5ms-1. At what height must a similar body be situated to have a potential energy equal in value with kinetic energy of the moving body?

.
A.

25.0m

B.

20.0m

C.

1.3m

D.

1.0m

10.

If a pump is capable of lifting 5000kg of water through a vertical height at 60m in 15min, the power of the pump is

.
A.

2.5 x 105Js-1

B.

2.5 x104Js-1

C.

3.3 x 103Js-1

D.

3.3 x 102Js-1

11.
The coefficient of friction between two perfectly smooth surface is
.
A. infinity
B. one
C. half
D. zero

12.
What effort will a machine of efficiency 90% apply to lift a load of 180N if its efforts am is twice as long as its load arm?
.
A. 80N
B. 90N
C. 100N
D. 120N.

13.
Calculate the work done when a force of 20N stretches a spring by 50mm.
.
A. 0.5J
B. 1.5J
C. 2.0J
D. 2.5J.

14.

At what depth below the sea-level would one experience a change of pressure equal to one atmosphere?

[density of sea water = 1013kg-3 one atmosphere = 0.01 x 105Nm-2 g= 10ms-2]

.
A.

0.1m

B.

1.0m

C.

10.0m

D.

100.0m.

15.

What volume of alcohol will have same mass as 4.2m-3 of petrol?

[density of alcohol = 8.4 x 102kgm-3 , density of petrol = 7.2 x 103kgm-3]

.
A.

0.8m3

B.

1.4m3

C.

3.6m3

D.

49.m3

16.

Calculate the length which corresponds to a temperature of 20ºC if the ice and steam points of an ungraduated thermometer are 400mm apart.

.
A.

20mm

B.

30mm

C.

60mm

D.

80mm

17.

A Wire of length 100.0m at 30°C has linear expansivity of 2 x 10-5K-1. Calculate Iength of the wire at a temperature of -10°C.

.
A.

100.08m

B.

100.04m

C.

99.96m

D.

99.92m.

18.

A gas at a pressure of 105Nm-2 expands from 0.6m-3 to 1.2m3 at constant temperature, the work done is

.
A.

7.0 x 106J

B.

6.0 x 106J

C.

6.0 x 105J

D.

6.0 x 104J

19.
Two liquids X and Y having the same mass are supplied with the same quantity of heat. If the temperature rise in X is twice that of Y, the ratio of specific heat capacity of X to that on is
.
A. 2:1
B. 1:2
C. 4: 1
D. 1:4.

20.
Foods cook quicker in salt water than in pure water because of the effect of
.
A. dissolved substances on the boiling point
B. atmospheric pressure on the boiling point
C. food nutrients on the thermal energy
D. salts on the thermal conductivity of water.

21.
Steam from boiling water causes more damage on the skin than does boiling water because
.
A. water has a high Specific heat
B. steam has latent heat of fusion
C. the steam is at a higher temperature than the water
D. steam brings heat more easily by convection.

22.

What will happen to the boiling point of pure water When it is heated in a place 30m below sea level?

.
A.

It will be more than 100°C

B.

It will be less than 100°C

C.

It will still be at 100°C

D.

It will be fluctuating.

23.
The rise or fall of a liquid in a narrow tube is because of the
.
A. viscosity of the liquid
B. surface tension of the liquid
C. friction between the walls of the liquid
D. osmotic pressure of the liquid.

24.
The mechanism of heat transfer from one point to another through the vibration of the molecules of the medium is
.
A. convection
B. conduction
D. diffusion.

25.

A wave that travels through stretched strings is known as

.
A.

electromagnetic wave

B.

micro wave

C.

mechanical wave

D.

seismic wave.

26.
A transverse wave and a longitudinal wave travelling in the same direction in a medium differ essentially in their
.
A. frequency
B. amplitude
C. direction of vibration of the particles of the medium
D. period of vibration of the particles ofthe medium.

27.

What is the velocity of sound at 100°C if the velocity of sound at 0°C is 340ms-1?

.
A.

497m-1

B.

440m-1

C.

397m-1

D.

240m-1

28.
If a sonometer has a fundamental frequency of 450Hz, what is the frequency of the fifth overtone
.
A. 2700Hz
B. 456Hz
C. 444Hz
D. 75Hz.

29.
A man 1.5m tall is standing 3m in front of a pinhole camera whose distance between the hole and the screen is 0.1m. What is the height of the image of. the man on the screen?
.
A. 0.05.1m
B. 0.15m
C. 0.30m
D. 1.00m.

30.

A ray of light passing through the centre of curvature of a concave mirror is reflected by the mirror at

.
A.

B.

45°

C.

90°

D.

180°

31.

From the diagram above, calculate the incident angle i.

.
A.

41°

B.

49°

C.

55°

D.

61°

32.
Total internal reflection will not occur when light travels from
.
A. water to air
B. water into glass
C. glass to air
D. glass into water.

33.

What does the diagram above represent?

.
A.

telescope in normal use

B.

microscope in normal use

C.

telescope in abnormal use

D.

microscope in abnormal use.

34.
if the linear magnification of the objective and eyepiece convex lenses of a compound microscope are 4 and 7 respectively, calculate the angular magnification of the microscope.
.
A. 2
B. 3
C. 11
D. 28

35.

The angle of deviation of light of various colours passing through a triangular prism increases in the order

.
A.

red → green → blue

B.

green → violet → blue

C.

blue → red → green

D.

blue → green → red.

36.

Calculate the force acting on an electron of charge 1.5 x 10-19C placed in an electric field of intensity 105Vm-1.

.
A.

1.5 x 10-11N

B.

1.5 x 10-12N

C.

1.5 x 10-13N

D.

1.5 x 10-14N.

37.
Capacitors are used in the induction coil to
.
A. control circuits
B. dissipate energy
C. prevent electric sparks
D. prevent distortion of electric fields.

38.

A cell of emf 1.5V is connected to series with a 1Ω resistor and a current of 0.3A flows through the resistor. Find the internal resistance of the cell.

.
A.

4.0Ω

B.

3.0Ω

C.

1.5Ω

D.

1.0Ω

39.
Which of the following obeys ohms laws?
.
A. electrolytes
B. metals
C. diode
D. glass.

40.
A house has ten 40W and five 100W bulbs. How much will it cost the owner of the house to keep them lit for 10 hours if the cost of a unit is N5?
.
A. N90
B. N50
C. N45
D. N40

41.
An electric device is rated 2000V, 250V. Calculate the maximum current it can take.
.
A. 9A
B. 8A
C. 7A
D. 6A.

42.
When a charge moves through an electric circuit in the direction of an electric force. it
.
A. gains both potential and kinetic energy
B. gains potential energy and loses kinetic energy
C. loses potential energy and gains kinetic energy
D. loses both potential and kihetic energy.

43.
To convert a galvanometer to a voltmeter, a
.
A. high resistance is connected to it in series
B. high resistance is connected to it in parallel
C. low resistance is connected to it in series
D. low resistance is connected to it in parallel.

44.

Induced emfs are best explained using

.
A.

Ohm's law

B.

C.

Colomb's law

D.

Lenz's law.

45.
If a current of 2.5A flows through an electrolyte for 3 hours and l.8g of a substance is deposited, what is the mass of the substance that will be deposited if a current of 4A flows through it for 4.8 hours?
.
A. 2.4g
B. 3.2g
C. 4.6g
D. 4.8g.

46.
Calculate the energy of the third level of an atom if the ground state energy is-24.8eV
.
A. -9.20eV
B. -8.20eV
C. -2.75eV
D. - 1.75eV.

47.
In photo-emission, the number of photoelectrons ejected per second depends on the
.
A. frequency of the beam
B. work function of the metal
C. threshold frequency of the metal
D. intensity of the beam.

48.
The particle nature of light is demonstrated by the
.
A. photoelectric effect
B. speed of light
C. colours of light
D. diffraction of light.

49.

The energy of a photon having a wavelength of 10-10m is

(h = 6.63 x 10-34Js c = 3.0 x108ms-1).

.
A.

2.0 x 10-15J

B.

1.7 x 10-13J

C.

2.0 x 10-12J

D.

1.7 x 10-12J

50.
The bond between Silicon and germanium
.
A. dative
B. covalent
C. trivalent
D. ionic.