Science

Electric Current and its Effects

Question:

Fig. 14.11 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.

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Answer:

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Electric Current and its Effects

Q 1.

Name any two effects of electric current.

Q 2.

Fill in the blanks:
(a) Longer line in the symbol for a cell represents its ___________terminal
(b) The combination of two or more cells is called a ____________.
(c) When current is switched ‘on' in a room heater, it ___________.
(d) The safety device based on the heating effect of electric current is called a _____________.

Q 3.

Will the compass needle show deflection when the switch in the circuit shown by fig. 14.15 is closed?

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Q 4.

When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.

Q 5.

Mark ‘T' if the statement is true and ‘F' it is a false:
(a) To make a battery of two cells, the negative terminal of one cell is connected to the negative terminal of the other cell. [T/F]
(b) When the electric current through the fuse exceeds a certain limit , the fuse wire melts and breaks. [T/F]
(c) An electromagnet does not aatract a piece of iron. [T/F]
(d) An electric bell has an electromagnet. [T/F]

Q 6.

Fig. 14.11 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.

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Q 7.

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.

Q 8.

Draw the circuit diagram to represent the circuit shown in fig. 14.9.

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Q 9.

Zubeda made an electric circuit using a cell holder shown in fig. 14.16, a switch and a bulb. When she put the switch in the ‘ON' position, the bulb did not glow. Help Zubeda in identifying the possible defects in the circuit.

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Q 10.

In the circuit shown in fig. 14.17.

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Would any of the bulb glow when the switch is in the ‘OFF' position?
What will be the order in which the bulbs A, B and C will glow when the switch is moved to the ‘ON' position?

Q 11.

The bulb in the circuit shown in fig. 14.13 does not glow. Can you identify the problem? Make necessary changes in the circuit to make the bulb glow.
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Q 12.

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 the ‘ON' position and battery.

Q 13.

Do you think an electromagnet can be used for separating plastic bags from a garbage heap? Explain.