electric current and magnetism - Category wise Question and Answer Practice Test with Solutions

Question : 21

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 : 22

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 : 23

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 : 24 [IAS (Pre) 2005]

What is the order of magnitude of electric resistance of the human body (dry)?

a) $10^6$ ohm

b) $10^2$ ohm

c) $10^4$ ohm

d) $10^8$ ohm

Question : 25

In a transistor

a) collector is more highly doped than emitter

b) both are equally doped

c) emitter is more highly doped than collector

d) None of the above