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BITSAT2015PhysicsCurrent ElectricityActual

A constant voltage is applied between the two ends of a uniform metallic wire. Some heat is developed in it. The heat developed is doubled if

Options

  1. Aboth the length and the radius of the wire are halved.
  2. Bboth the length and the radius of the wire are doubled.
  3. Cthe radius of the wire is doubled.
  4. Dthe length of the wire is doubled.

Correct answer

B. both the length and the radius of the wire are doubled.

Step-by-step solution

The heat produced is given by H= V² R and R= r² H=V² ( r² ) or H= ( V² ) r² Thus heat (H) is doubled if both length ( ) and radius (r) are doubled.

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