An electric motor is a device which transforms :
mechanical energy to electrical energy
heat energy to electrical energy
electrical energy to heat energy only
electrical energy to mechanical energy
The north-south polarities of an electromagnet can be found easily by using :
Fleming's right-hand rule
Fleming's left-hand rule
Clock face rule
Left-hand thumb rule
A fuse wire is always connected to:
Earth wire
Neutral wire
Live wire
Between live and neutral lines
A switch is always connected to the
earth wire
neutral wire
live wire
none of these
A d.c. generator is based on the principle of :
electrochemical induction
electromagnetic induction
magnetic effect of current
heating effect of current
The unit of magnetic field is
weber
gauss
tesla
weber/m2
A fuse is used in mains electric supply as a safety device. Which one of the following statements about the fuse is correct?
It is connected in parallel with the main switch.
It is made mainly from silver alloys.
It must have a low melting point.
It must have a very high resistance
An MCB which cuts off the electricity supply in case of short-circuiting or overloading works on the :
chemical effect of current
electroplating effect of current
According to International convention of colour coding of insulation of wires in a cable :
live is red, neutral is blue and earth is brown
live is red, neutral is green and earth is black
live is brown, neutral is blue and earth is black
live is brown, neutral is light blue and earth is green
The frequency of AC used in India is
50 Hz
100 Hz
200 Hz
1/100 Hz
