Advertisements
Advertisements
Question
What is meant by ‘MCB’? Which part of the domestic electric circuit does it replace?
Advertisements
Solution
‘MCB’ stands for ‘miniature circuit breaker’. This is a device that automatically ‘switches off the mains supply if the current drawn Exceeds the prescribed upper safe limit. It can be ‘reset’ with the help of a flip-over switch. It protects the entire circuit and appliances against short circuiting, etc.
APPEARS IN
RELATED QUESTIONS
A switch is not touched with wet hands while putting it on or off. Give a reason for your answer.
The following diagram shows three lamps and three switches 1, 2 and 3 connected with two cells.
- Name the switch / switches to be closed so as to light all the three lamps.
- How are the lamps connected: in series or in parallel?

The diagram below shows a dual control switch circuit connected to a bulb.

(i) Copy the diagram and complete it so that the bulb is switched ON.
(ii) Out of A and B which one is the live wire and which one is the neutral wire ?
It is dangerous to connect the switch in the neutral wire. Explain your answer.
What are ‘dual switches’? Mention their one main use.
Complete the drawing shown in Figure to indicate where the free ends of the two wires should be joined to make the bulb glow.

Would the bulb glow in the circuit shown in Figure?

In which position is the key placed in a circuit?
Name the component which connects electrical components to one another.
Name the wire to which a switch is connected.
