Electric Current and its Effects
1. Draw in your notebook the symbols to represent the following components of electrical circuits. Connecting wires, switch in the OFF position, bulb, cell, switch in ON position and battery.
2. Draw the circuit diagram to represent the circuit shown in Fig.
3. Fig. Shows four cells fixed on a board. Draw lines to indicate how you will connect their terminals with wires to make a battery of four cells.
4. The bulb in the circuit shown in Fig. does not glow. Can you indicate the problem? Make necessary changes in the circuit to make the bulb glow.
5. Name any two effects of electric current.
6. When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.
7. Will the compass needle show the deflection when the switch in the circuit shown by Fig. is closed?
8. Fill in the blanks
(a) Longer line in the symbol represents its ————- terminal.
(b) The combination of two or more cell is called ——–.
(c) When a current is switched ON in a room heater, it ——–.
(d) The safety device based on the heating effect of electric current is called ——-.
9. Mark ‘T” if the statement is true and ‘F’ if it is false:
(a) To make a battery of two cells, the negative terminal of one cell is connected to the negative terminal of other cell. (T/F)
(b) When the current through the fuse exceeds a certain limit, the fuse wire melts and breaks. (T/F)
(c) An electromagnet does not attract a piece of iron. (T/F)
(d) An electric bell has an electromagnet. (T/F)
10. Do you think an electromagnet can be used for separating plastic bags from a garbage heap? Explain.
11. An electrician is carrying out some repairs in your house. He wants to replace a fuse by a piece of wire. Would you agree? Give reasons for your response.
12. Zubeda made an electric circuit using a cell holder shown in Fig., a switch and a bulb. When she put she switch in the ON position, the bulb did not glow. Help Zubeda in identifying the possible defects in the circuit.
13. In the circuit shown in Fig.
(i) Would any of bulb will glow when the switch is in the ‘OF’ position?
(ii) What will be the order in which bulb A, B, C will glow when switch is moved to the ‘ON’ position?