A) In (i) only
B) In (ii) only
C) In each case, power loss is zero
D) Data is insufficient
Correct Answer: A
Solution :
Power dissipated is given by \[P=VI\] where V is voltage and \[I\] is current. First case, \[{{I}_{1}}=\frac{P}{{{V}_{1}}}=\frac{100\times {{10}^{6}}}{20000}=5000A\] Second case, \[{{I}_{2}}=\frac{P}{{{V}_{2}}}=\frac{100\times {{10}^{6}}}{200}=500000\,A\] Also, power dissipated is given by \[P={{I}^{2}}R\] where R is resistance of the cable. \[\therefore \] \[{{P}_{1}}={{(5000)}^{2}}R=25\times {{10}^{6}}R\] \[{{P}_{2}}={{(500000)}^{2}}R=25\times {{10}^{10}}R\] \[\Rightarrow \] \[{{P}_{1}}<{{P}_{2}}\]
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