Page 99 - Physics_Form_2

Current electricity

14. Figure 2.72 shows three resistors (a) What is the total resistance in the

connected in parallel to a cell with circuit?
negligible internal resistance. (b) What is the total current flowing in
the circuit?
(c) What current flows in each resistor?
FOR ONLINE READING ONLY
15 v 10 Ω 15 Ω 20 Ω (d) How much power is supplied by the

battery?
(e) How much power is dissipated in
each resistor?
Figure 2.72

15. An electrical circuit in a domestic house is protected by a 6 A fuse. The circuit
is connected to the 240 V mains. The following appliances in Table 2.11 are
connected to the circuit.

Appliance Bulb 1 Bulb 2 TV Heater Iron
Power rating (W) 100 75 300 1500 900

List several groups of these appliances that could be turned ON at the same time
without blowing the fuse. Justify your answer.

16. Look at the circuit diagram in Figure 17. Study the following diagram of

2.73. Each light bulb is identical. Figure 2.74.
A

1 4

2
B C

3

Figure 2.73 Figure 2.74
(a) Is this a series or parallel circuit? (a) What is the relationship between the
Explain your answer. ammeter readings on A1 and A4?
(b) How do the brightness of bulbs In other words, how do the current
strengths compare at these points in
A, B and C compare? (which is the circuit? Explain your answer.
the brightest?)
(c) What would happen to the (b) What is the relationship between the
ammeter readings on A , A and A ?
3
2
1
brightness of the bulbs if the In other words, how do the current
switch was opened? Explain strengths compare at these points in
your answer. the circuit? Explain your answer.
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Physics Form 2 Final.indd 93 25/10/2025 10:26