Electric Current and its Effects
Revision Worksheet
Fill in the blanks :
1. A thin wire in the bulb that glows when an electric current passes through it
is called the ____________________.
2. When the bulb gets _______________, its filament is broken.
3. The coil of wire in an electric heater is known as ________________.
4. The amount of heat produced in a wire depends on its, ______________,
________________ and __________________.
5. When an electric current flows through a wire, it behaves like a
_________________.
6. The ___________of an electric bell acts as an electromagnet in its working.
II State whether the following statements are True or False :
1. When the electric current is switched off, the coil generally loses its
magnetism.
2. The wires used for making electric circuits do not normally become hot.
3. The filament of an electric bulb never gets heated.
4. In a battery, the electric cells are always placed one after the other.
5. Connecting many devices in a single socket does not affect the flow of
current in a circuit.
6. Wear and tear of insulated wires can cause short circuits.
7. CFLs consume more electricity than ordinary bulbs.
III Name the following :
1. The name of the scientist who first noticed the magnetic effect of current.
2. The switches being used in place of fuses.
3. A diagram made using symbols of electric components.
4. The mark of safety necessary on electrical appliances.
IV Define :
1. Battery
2. Electromagnet
3. Fuse
Answer the following-
Q.1. Name the device which helps in breaking or completing a circuit?
Q.2. Who observed the magnetic effect of current for the first time?
Q.3. What is the glowing part of a bulb called?
Q.4. When is the bulb is said to be fused?
Q.5. Draw a circuit diagram showing a bulb, a closed switch & a battery of four
cells. Also show the direction of current flowing through the circuit.
Q.6. What do you understand by the 'heating effect of current'?
Q.7. What is an electric fuse? Explain the working of an electric fuse.
Q.8. What do you understand by magnetic effect of current?
Q.10. What is an electromagnet? State the various uses of an electromagnet.
Q.11. Give reason:
An electric bulb gives out light when connected in a circuit & switched on.
Q.12. Manav made an electric circuit & placed a magnetic compass near it.
(a) On switching on, the needle of the magnetic compass showed a deflection
Why?
(b) On switching off, the needle came back to its normal north-south direction.
Why?
