Current Electricity

JEE Main level, single correct, medium

274 of 380

Question 274 of 380

A wire when connected to 220 V220 \mathrm{~V} mains supply has power dissipation P1\mathrm{P}_1. Now the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is P2P_2 Then P2:P1P_2: P_1 is

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Answer: (B) 4

P1=V2/R;P2=V2(R/2)+V2(R/2)=4V2R=4P1P_1=V^2 / R ; P_2=\frac{V^2}{(R / 2)}+\frac{V^2}{(R / 2)}=4 \frac{V^2}{R}=4 P_1

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