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

1

(a)

the glass case of the bulb

(b)

the thin filament

(c)

the thick wires supporting the filament

(d)

gases inside glass case of the bulb

In the circuit shown in figure, when the switch is moved to ON position.

1

(a)

the bulb A will glow first

(b)

the bulb B will glow first

(c)

the bulb C will glow first

(d)

all bulbs will glow together

Choose the figure from the options (a), (b), (c) and (d) given below which shows the correct direction of current.

1

(a)

(b)

(c)

(d)

In the following arrangement shown in figure, the bulb will not glow if the ends A and B are connected with

1

(a)

a steel spoon

(b)

a metal clip

(c)

a plastic clip

(d)

a copper wire

Which of these uses a chemical reaction to produce an electric current?

1

(a)

An electric generator

(b)

A dry cell

(c)

Wind mill

(d)

Al lof these

Non-metals like________ and ____________ are good conductors of electricity.

1

(a)

Wood and paper

(b)

Graphite and gas carbon

(c)

Glass and rubber

(d)

None of these

What is used in making or breaking a circuit?

1

(a)

Plug

(b)

Battery

(c)

Wire

(d)

Switch

A complete circuit contains bulb_____________ and_________________

1

(a)

switch, cell

A power station provides us __________________

1

(a)

electricity

A magnet always has _________poles.

1

(a)

two

The device used to break an electric circuit is called________.

1

(a)

switch

The above symbol is of switch.

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(a) True

(b) False

Dry cell converts electrical energy into chemical energy.

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(a) True

(b) False

How does an electric bulb glow?

1

(a)

When current passes through filament, it gets red hot and emits light.

Fig. shows a bulb with its different parts marked as 1, 2, 3, 4 and 5. Which of them label the terminals of the bulb?

1

(a)

Label 3 and 4 show the terminals of the bulb.

Paheli wanted to glow a torch bulb using a cell. She could not get connecting wires instead she got two strips of aluminium foil. Will she succeed? Explain how.

2

(a)

Name two insulators and two conductors.

2

(a)

How can you explain that the human body is a good conductor of electricity?

2

(a)

Why is it compulsory to keep a fire extinguisher near the meter room of housing societies?

2

(a)

Due to Sudden power failure in Ravi's house, he lighted three candles. He placed one of them in the drawing room, second in the kitchen for his mother and third one in his grandmother's room as she was ailing and bed-ridden.
(i) What is the importance of light in one's life?
(ii) What is the chemical transformation in a candle?
(iii) What values are exhibited by Ravi?

2

(a)

Complete the drawing shown in the figure to indicate where the free ends of the two wires should be joined to make the bulb glow.

3

(a)

As we know that silver is the best conductor of electricity instead of this we use copper and aluminium. Why?

3

(a)

Why do bulbs have two terminals?

3

(a)

Sita is operating an base electric wire so that its electric iron can be used safely. Her friend Vimlesh advised her not to do so without plastic gloves.
(a) Mention the values that Vimlesh shows here.
(b) A plastic glove is an insulator or conductor.

3

(a)

How does an electric cell produce electricity?

3

(a)

In figures A and B, show a bulb connected to a cell in two different ways.
(a) Mention the direction of the current through the bulb in both the cases (Q to P or P to Q)?
(b) Will the bulb glow in both the cases?
(c) Does the brightness of the glowing bulb depend on the direction of current through it?

5

(a)

Think of six activities which use electric current Also name the devices used to perform the activity.

	Activity you perform	Device
Example:	Get light	Torch
	___________	.......................
	___________	.......................
	___________	.......................
	___________	.......................
	___________	.......................

5

(a)