JEE Main · 2023 · 06 Apr 2023 · Shift 1 · Alternating Current

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An ideal transformer with purely resistive load operates at 12 kV on the primary side. It supplies electrical energy to a number of nearby houses at 120 V. The average rate of energy consumption in the houses served by the transformer is 60 kW. The value of resistive load (Rs) required in the secondary circuit will be

____

m Ω

Answer: 240

Solution

For an ideal transformer, power is conserved:

P_{s} = P_{p} = 60

kW. The secondary voltage is

V_{s} = 120

V, so the secondary current is

I_{s} = \frac{P _{s}}{V _{s}} = \frac{60 \times 1 0 ^{3}}{120} = 500

A. The resistive load in the secondary is

R_{L} = \frac{V _{s}}{I _{s}} = \frac{120}{500} = 0.24Ω = 240 m Ω

JEE Main · 2023 · 06 Apr 2023 · Shift 1 · Integer answer

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