Electric Bulb and Its Working

Q.

What are the main components of an electric circuit?

1. Wires
2. Electric cell
3. Load
4. Switch

Q.

State three characteristics of a parallel circuit.

Q. What happens if we connect a fused bulb in an electric circuit?

1. The bulb burns immediately.
2. There is closed path for the flow of electricity.
3. The bulb doesn't glow at all.
4. The bulb glows brightly.

Q.

What is phase wire?What is the function of phase wire and neutral wire?

Q.

Can we use the same fuse in a geyser and a television set? Explain.

Q.

Why is an electric fuse required in all electrical appliances?

Q.

Question 18

A fused bulb does not glow. Why?

Q.

Question 13

A torch requires 3 cells. Show the arrangement of the cells, with a diagram, inside the torch so that the bulb glows.

Q.

Question 3

In an electric bulb, light is produced due to the glowing of

(a) the glass case of the bulb.

(b) the thin filament.

(c) the thick wires supporting the filament.

(d) gases inside the glass case of the bulb.

Q. How does the cell of a torch help its bulb to glow?

Q.

When you switch on an electric bulb, it glows. Can you tell what makes it glow?

1. gases inside the glass case of the bulb

2. the thin filament

3. the glass case of the bulb

4. the thick wires supporting the filament

Q.

Question 6

Filament of a torch bulb is

(a) A metal case.

(b) Metal tip at the centre of the base.

(c) Two thick wires

(d) A thin wire.

Q. The electric current in a closed circuit always flows from the _____ terminal of the electric cell to the _______ terminal.

1. positive (+), negative (-)
2. negative (-), positive (+)
3. negative (-), negative (-)
4. positive (+), positive (+)

Q. What is the function of the filament in the bulb? Explain the mechanism of their working. What other materials can be used to make a filament? [5 MARKS]

Q.

Why does the filament of a bulb fuse and break even if there is no oxygen to burn it?

Q.

Why doesn't a fused bulb glow when connected across a battery ?

Q.

………. is used with phosphors in fluorescent lamp

Q.

What is meant by rating of an electrical appliances?

Q.

What is the value of fuse wire used in main power circuit in household?

Q. There are terminals in an electric cell.

1. four
2. two
3. three

Q. When two bulbs are connected in parallel and one bulb blows out, what happens to the other bulb?

Q.

Electrical component that limits the flow of electrical current in a circuit is called

1. switch

2. resistor

3. electric cell

4. electric bulb

Q.

At what voltage is the current available at our household?

Q.

What type of energy change takes place in lighting a torch?

Q.

Two bulbs when connected in series are brighter than a single bulb.

1. True
2. False

Q. Why do electricians wear rubber gloves?

Q.

Why is the excessive continued overloading dangerous?

Q. Which part of this electric torch can open or close the circuit?

1. 
2. 
3. 

Q.

What should be the properties of a fuse wire?

Q.

Why is fuse wire always placed in the live wire of an electric circuit?