In an elastic collision, momentum is conserved as well as well as?
Απάντηση
(B)
kinetic energy
4
The induced current in a coil always flows in a direction so as to oppose the change that causes it. This statement is known as
Απάντηση
(B)
Lenz's law
5
Which of the following instruments can be used to compare the magnitudes of charges on two given bodies?
Απάντηση
(C)
Gold-leaf electroscope
6
A body of mass 2 kg is released from a point 100 m above the ground. Calculate its kinetic energy 80m from the point of release.
Απάντηση
(A)
1600 J
7
Which of the following waves is not mechanical?
Απάντηση
(C)
Radio waves
8
A loaded spring is set in simple harmonic motion. The force that tends to restore the load to its equilibrium position is
Απάντηση
(D)
gravitational
9
Which of the following cases cannot produce total internal reflection? A light ray travelling from
Απάντηση
(C)
air to water
10
The vacuum in a thermoflask reduces heat loss resulting from
Απάντηση
(B)
conduction and convection only
11
The diagram above represents an experimental set-up for verifying?
Απάντηση
(A)
lens formula
12
Which of the following statements about a moving object is correct?
Απάντηση
(C)
At a steady velocity, the resultant force acting on it must be equal to zero
13
If the efficiency of a transformer is 100%, which of the following equations would be correct?
Απάντηση
(D)
I\(_p\)E\(_s\) = I\(_s\)E\(_p\)
14
A freshly demagnetized bar magnet is placed in the East-West direction to ensure that
Απάντηση
(A)
the molecular magnets remain randomly arranged.
15
Which of the following graphs above of a charge Q against potential difference V across the capacitor is correct?
Απάντηση
(B)
B
16
A small amount of air is introduced into the vacuum above the mercury in a mercury barometer tube. The mercury level goes down because the air molecules
Απάντηση
(B)
increase the pressure above the mercury.
17
Calculate the quantity of heat needed to change the temperature of 60g of ice at 0 °C to 80 °C. [specific latent heat of fusion of ice= 3.36 x 10\(^5\) Jkg\(^{-1}\) specific heat capacity of water 4.2 x 10\(^3\) J kg\(^{-1}\) K\(^{-1}\)]
Απάντηση
(C)
40.32 kJ
18
The wire of a platinum resistance thermometer has d resistance of 3.5\(\Omega\) at 0 °C and 10.52\(\Omega\) at 100°C. Calculate the temperature of the wire when its resistance is 7.5\(\Omega\).
Απάντηση
(D)
57 \(^o\)C
19
A transverse pulse of frequency 9 Hz traves 4.5m in 0.6 s. Calculate the wavelength of the pulse.
Απάντηση
(C)
0.83 m
20
In which of the following media is the speed of sound the least?
Απάντηση
(A)
Air
21
Which of the following characteristics of waves can a ripple tank be used to demonstrate?
I. Reflection
II. Refraction
III. Diffraction
Απάντηση
(A)
I, II and Ill
22
Which of the following graphs gives the correct relationship between energy and mass when mass is converted to energy.
Απάντηση
(B)
B
23
An 800 kg car moving at 80 km hr\(^{-1}\) collides with a 1200 kg car moving at 40 km hr\(^{-1}\) in the same direction. If the cars stick together, calculate their common velocity.
Απάντηση
(D)
56 km hr\(^{-1}\)
24
The mass of a load is doubled while the force acting on it is halved. The resulting acceleration of the load is
Απάντηση
(B)
quartered
25
The maximum and minimum thermometer reads the
Απάντηση
(D)
the maximum temperature during the day and minimum temperature at night from the last reset
26
An a.c. the generator can be converted to a d.c. generator by replacing the
Απάντηση
(D)
slip rings with a commutator
27
Which of the following statements is the correct reason for using soft iron in making the armature or an electric bell?
Απάντηση
(B)
It loses its magnetism readily
28
The diagram above illustrates a meter bridge circuit underbalanced conditions. Determine the value of x.
Απάντηση
(A)
50.cm
29
Which of the following devices is used for storing electric charges?
Απάντηση
(D)
Capacitor
30
An electron of mass 9.1 x 10\(^{-31}\) kg moves with a speed of 2.0 x 10\(^6\) ms\(^{-1}\) round the nucleus of an atom in a Circular path of radius 6.1 x 10(^{11}\) m. Determine the angular speed of the electron.
Απάντηση
(A)
3.28 x 10\(^{16}\) rad s\(^{-1}\)
31
An electron of mass 9.1 x 10\(^{-31}\) kg moves with a speed of 2.0 x 10\(^6\) ms\(^{-1}\) round the nucleus of an atom in a Circular path of radius
6.1 x 10\(^{11}\) m. Calculate the centripetal force acting on the electron.
Απάντηση
(B)
6.0 x 10\(^{-8}\)N
32
A device consumes 100 W of power when connected to a 120 V source. Calculate its resistance.
Απάντηση
(D)
144\(\Omega\)
33
Which property of a wave remains constant when the wave travels from one medium into another?
Απάντηση
(D)
Frequency
34
The anomalous expansion of water occurs in the range
Απάντηση
(B)
0 °C to 4 °C
35
A ray of light traveling from a rectangular glass block of refractive index 1.5 into air strikes the block at an angle of incidence of 30. Calculate its angle of refraction.
Απάντηση
(A)
48.6°
36
A rectangular piece of iron measuring 4 cm by 3 cm at 20\(^o\)C is heated until its temperature increases by 100 C. Calculate the new area of the metal. [Linear expansivity of iron is 1.2x 10\(^{-5}\) K\(^{-1}\)]
Απάντηση
(C)
12.0288 cm\(^3\)
37
Two bodies of masses 3.0 kg and 2.0 kg are separated by a distance of 50 cm. Calculate the force of attraction between them. [G = 6.67 x 10\(^{-11}\) Nm\(^2\) kg\(^2\)]
Απάντηση
(A)
1.6 x 10\(^{-9}\)N
38
The diagram above illustrates an object moving in a circular path at a constant speed. Which of the arrows indicates the direction of linear velocity?
Απάντηση
(A)
z
39
Which of the following thermometers is used to measure the temperature of the human body?
Απάντηση
(B)
Alcohol-in-glass thermometer
40
In the diagram above, the time taken to trace a wave between P and Q is?
Απάντηση
(A)
2 periods
41
Which of the following materials does not serve as a safety device in electrical circuits?
Απάντηση
(A)
Connecting wires
42
Which of the following liquids has the highest surface tension?
Απάντηση
(B)
Cold water
43
The nucleon and proton numbers of a neutral atom of an element are 238 and 92 respectively. Determine the number of neutrons in the atom.
Απάντηση
(D)
146
44
An instrument used to measure relative humidity is the?
