Two resistors R1 and R2 are connected up in a circuit as shown in the figure below. When the switch S is open, the ammeter reads 1 A and the voltmeter reads 8 V. When the switch S is closed, the ammeter reads 1.5 A and the voltmeter reads 6 V.
Calculate the value of R1 and R2.
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Answer:
When Switch S is opened,
I = 1 A, V = 8 V
R2 = 8/1 Ω
R2 = 8 Ω
When Switch S is closed,
I = 1.5 A, V = 6 V
(1/R1 + 1/R2)-1 = 6/1.5 Ω = 4 Ω
1/R1 + 1/8 = 1/4
1/R1 = 1/4 - 1/8 = 1/8
Hence, R1 = 8 Ω
