set 2 MCQ Questions & Answers Detailed Explanation

Question : 1

Three bulbs of 40 W, 60 W and 100 W are connected in series to a current source of 200 V. Which of the following statements is true ?

a) 60 W bulb glows brightest

b) 100 W bulb glows brightest

c) 40 W bulb glows brightest

d) All bulbs glow with same brightness

Question : 2

n-p-n transistors are preferred to p-n-p transistors because:

a) they have low dissipation energy

b) they are capable of handling large power

c) they have low cost

d) electrons have high mobility than holes and hence high mobility of energy

Question : 3

Application of a forward bias to a p–n junction

a) increases the potential difference across the depletion zone.

b) increases the number of donors on the n side.

c) widens the depletion zone.

d) increases the electric field in the depletion zone.

Question : 4

Earth’s magnetic field always has a horizontal component except at

a) geographical north pole

b) magnetic equator

c) magnetic pole

d) at an altitude of 45°

Question : 5

A device which converts electrical energy into mechanical energy is

a) Electric motor

b) Dynamo

c) Transformer

d) Inductor

Question : 6

Consider the following statement: The principle of total internal reflection is applicable to explain the

1. Formation of mirage in desert.
2. Formation of image in microscope.
3. Colour of evening sky.
4. Operation of optical fibres.

a) 2 and 3

b) 1 and 4

c) 3 and 4

d) 1 and 2