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

Question : 11

The essential difference between an AC generator and a DC generator is that

a) DC generator will generate a higher voltage

b) AC generator will generate a higher voltage

c) AC generator has an electromagnet while a DC generator has permanent magnet

d) AC generator has slip rings while the DC generator has a commutator

Question : 12 [NDA]

What is the number of neutral points for a bar magnet with its north pole pointing geographical north?

a) Two

b) Zero

c) One

d) Infinite

Question : 13

Two identical conducting balls having positive charges q1 and q2 are separated by a distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

a) same as before

b) more than before

c) less than before

d) zero

Question : 14

What happens when some charge is placed on a soap bubble?

a) Its radius increases

b) The bubble collapses

c) Its radius decreases

d) None of these

Question : 15

In the symbol of a transistor , the arrow head points in the direction of flow of

a) electrons

b) majority carriers

c) holes

d) minority carriers