A d.c. generator is based on the principle of :
electrochemical induction
electromagnetic induction
magnetic effect of current
heating effect of current
At what voltage is the electric power generated at the power generating station?
11 kV
25 kV
21 kV
40 kV
The frequency of AC used in India is
50 Hz
100 Hz
200 Hz
1/100 Hz
A switch is always connected to the
earth wire
neutral wire
live wire
none of these
At the time of short circuit, the current in the circuit :
reduces substantially
does not change
increases heavily
varies continuously
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
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
Magnetic lines of force
are mere directions
have no physical reality
can be used to indicate the direction of the magnetic of the magnetic field of a point
all the above are correct
Circuit Breaker Device which can be used in place of fuse wire in domestic electric wiring is called :
CBD
DCB
MCD
MCB
The electric appliances in a house are connected in
series
parallel
either series or parallel
both in series and parallel
