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JEE Main 2019 (11 Jan, Shift 1) · Electrical Power & Heating Effect

Electrical Power & Heating Effect question from JEE Main 2019 (11 Jan, Shift 1)

Q40JEE Main 2019 · 11 JAN · SHIFT 1Easy

Electrical Power & Heating Effect

Two equal resistances when connected in series to a battery, consume electric power of 60 W. If these resistances are now connected in parallel combination to the same battery, the electric power consumed will be:

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Answer: (a)

  1. P=V2ReqP = \frac{V^2}{R_{eq}} at fixed VV.
  2. Series Req=2RR_{eq} = 2R, parallel Req=R2R_{eq} = \frac{R}{2}: ratio of resistances 4:14 : 1.
  3. Pp=4Ps=4×60=240 WP_p = 4 P_s = 4 \times 60 = 240\ \text{W}.
  4. So the answer is (a) 240 W.
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