Page 136 - Science Class 07

2. What advantages can we get from the hea ng effects of electricity?
3. Why is filament of an electric bulb made from tungsten?

4. What is short circuit? What do we use to avoid short circuit?
5. What is the importance of a fuse? Write the types of fuse.
6. What is electromagnet? Why is it used in medical field?

Project
Project ActivityActivityActivity
Project
Project Activity
A. Take a ba ery (which is used in torch) wire, bulb (used in torch) and a switch. Make an electric
circuit using these objects. Cut a small piece from the wire and join it using objects made of
different materials one-by-one and find out whether the object you used is a conductor or
insulator.

B. Draw a neat and clean diagram of open and closed circuit.

Open circuit Closed circuit

C. Draw the symbols for the following.

Cell
Ba ery

Switch on

Voltmeter

Conduc ng wire
Switch off

Lamp

Ammeter

HO
HOTSTSTS
HO
HOTS
A. Fuse wires are not used in a circuit containing electric cells why?
B. Can you use a copper wire to make the filament of an electric bulb? Why?

136 Science-7