set 3 MCQ Questions & Answers Detailed Explanation

Question : 1

Match Column I and Column II.

a) A – 4 ; B – 2 ; C – 1 ; D – 3

b) A – 2 ; B – 1 ; C – 4 ; D – 3

c) A – 3 ; B – 4 ; C – 1 ; D – 2

d) A – 2 ; B – 4 ; C – 1 ; D – 3

Question : 2

Electromagnetic waves with frequencies greater than the critical frequency of ionosphere cannot be used for communication using sky wave propagation because:

a) The refractive index of the ionosphere becomes very low for f > $f_ c$

b) The refractive index of the ionosphere very high for f < $f_c$

c) The refractive index of the ionosphere becomes very high for f > $f_c$

d) None of the these

Question : 3

Telephony is an example of ________ mode of communication

a) broadcast

b) both (a) and (c)

c) point-to-point

d) None of these

Question : 4

Consider the following statements: In a nuclear reactor, self-sustained chain reaction is possible, because:

1. More neutrons are released in each of the fission reactions.
2. The neutrons immediately take part in the fission process.
3. The fast neutrons are slowed down by graphite.
4. Every neutron released in the fission reaction initiates further fission.

a) 1 and 3

b) 2 and 4

c) 1, 2 and 3

d) 2, 3 and 4

Question : 5

If an a-particle is projected normally through a uniform magnetic field, then the path of the a-particle inside the field will be

a) parabolic

b) elliptical

c) circular

d) a straight line

Question : 6

Television signals are

a) amplitude modulated

b) both frequency and amplitude modulated

c) frequency modulated

d) phase modulated