21-The value of dielectric constant (permittivity) is determined by the speed of
(A) charges
(B) light
(C) glass rod
(D) atoms
22-The core of transformers should have
(A) high specific resistance
(B) high hysteresis
(C) high permeability
(D) low permeability
23-The work done in an adiabatic change in a gas depends on
(A) change in pressure
(B) change in volume
(C) change in temperature
(D) change in pressure and volume
24-For a semiconductor which of the following is true?
(A) Resistance is always zero
(B) Resistance is independent of temperature
(C) Resistance increases with increase of temperature
(D) Resistance decreases with increase of temperature
25- If k is the Boltzmann’s constant and T is the temperature, energy of a diatomic molecule is
(A) 5 kT
(B) (5/2)kT
(C) 7 kT
(D) (2/5)kT
26-What is the instrument used to measure the sugar content in a solution?
(A) spectrometer
(B) polarimeter
(C) refractometer
(D) grating
27- In the Carnot engine, when heat is taken from the heat source, what happens to the temperature of the source?
(A) remains constant
(B) doesn’t remain constant
(C) temperature increases
(D) temperature decreases
28- A light ray passing through a distance of L in a medium, of refractive index μ. Then the optical path length is equal to
(A) μL
(B) L/μ
(C) L
(D) (μ-1)L
29- To keep gravitational attractive force and surface forces of liquid drop equal, the liquid drop should have
(A) less surface energy
(B) high surface energy
(C) uniform surface energy
(D) non uniform surface energy
30- Which of the following statement is correct?
(A) Nuclear forces are gravitational forces
(B) Nuclear forces are electrostatic forces
(C) Nuclear forces are charge dependent
(D) Nuclear forces are short range forces
ANSWERS:
21-(B), 22-(C), 23-(C), 24-(D), 25-(B), 26-(B), 27-(A), 28-(B), 29-(A), 30-(D)