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Question
Two resistances R1 = 4Ω and R2 = 6Ω are connected in series. The combination is connected with a battery of e.m.f. 6V and negligible resistance. Calculate:
(i) the heat produced per minute in each resistor,
(ii) the power supplied by the battery.
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Solution
Given: R1 = 4Ω, R2 = 6Ω, E = 6V, t = 1 minute = 60s.
Total resistance of the circuit R = R1 + R2 = 4 + 6 = 10Ω
Current through the battery I = `"E"/"R" = 6/10 = 0.6` A
The same current flows through each resistor.
(i) The heat produced in resistor R1 is H1 = I2R1t
= (0.6)2 × 4 × 60 = 86.4 J
The heat produced in resistor R2 is H2 = I2R2t
= (0.6)2 × 6 × 60 = 129.6 J
(ii) The power supplied by the battery = E × I
= 6 × 0.6 = 3.6 W.
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