Power dissipated across the 8 Ω Ω resistor in the circuit s…

Physics Current Electricity Combination of Resistance MCQ (Single Correct)

Power dissipated across the 8 Ω Ω resistor in the circuit shown here is 2 watt. The power dissipated in watt units across the 3 Ω Ω resistor is:-

2.0

1.0

0.5

3.0

Text Solution

Verified by Experts

The correct answer is:

Resistances 1 Ω Ω and 3 Ω Ω are connected in series, so effective resistance

R' = 1 + 3 = 4 Ω Ω

Now, R' and 8 Ω Ω are in parallel. We known that potential difference across resistances in parallel order is same

Hence, R' × i 1 = 8i 2

or 4 × i 1 = 8i 2

or i 1 = i 2 = 2i 2 ......(i)

Power dissipated across 8 Ω Ω resistance is

i 2 2 (8) t = 2W

or i 2 2 t = = 0.25 W ......(ii)

Power dissipated across 3 Ω Ω resistance is

H = i 1 2 t

= (2i 2 ) 2 t

= 12i 2 2 t

but i 2 2 t = 0.25 W

H = 12 × 0.25 = 3W

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