NEET UG PHYSICS MCQ: CURRENT ELECTRICITY

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A block of metal is heated directly by dissipating power in the internal resistance of block. Because of temperature rise, the resistance increases exponentially with time and is given by

\mathrm{R}(\mathrm{t})=0.5 \, \mathrm{e}^{2 \mathrm{t}}

, where

\mathrm{t}

is in second. The block is connected across a

110 \mathrm{~V}

source and dissipates

7644 \mathrm{~J}

heat energy over a certain period of time. This period of time is ______

\times 10^{-1}

sec.

View answer and explanation

Correct option: A

Option A (5) is correct. The heat energy dissipated is given by the integral of power over time. Solving the integral yields a time of 0.5 seconds, which is 5 × 10^-1 seconds.

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