Alternating Current

JEE Main level, numerical answer, medium

175 of 190

Question 175 of 190

An ideal transformer with purely resistive load operates at 12kV12kV on the primary side. It supplies electrical energy to a number of nearby houses at 120V.120V. The average rate of energy consumption in the houses served by the transformer is 60kW.60kW. The value of resistive load (Rs)({R}_{s}) required in the secondary circuit will be_________m\Omega .

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Answer: 240

The given data is
P=60×103WP=60\times {10}^{3}W
Vs=120V{V}_{s}=120V
A transformer has a primary coil and a secondary coil.
The formula for the power delivered is given by
P=V2sRsP=\dfrac{{{V}^{2}}_{s}}{{R}_{s}}
⇒60×103=120×120Rs⇒Rs=120×12060×103=240mΩ\Rightarrow 60\times {10}^{3}=\dfrac{120\times 120}{{R}_{s}} \Rightarrow {R}_{s}=\dfrac{120\times 120}{60\times {10}^{3}}=240m\Omega

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