By what percentage will the illumination of the lamp decrease if the current drops by 20 % ?

By what percentage will the illumination of the lamp decrease if the current drops by 20%?
  1. 46%
  2. 26%
  3. 36%
  4. 56%

Solution

Power through the resistor is given by, P=I2R.

Now, Pint=I2intR

and Pfinal=0.8Iint2R

Therefore, % change in power =

Pfinal−PintPint×100=0.64−1×100=−36%

Asked in: JEE Main 2024 (31 Jan Shift 2)

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