The battery of a mobile phone is rated as 4.2 V , 5800 mAh. How much energy is stored in it when fully…

The battery of a mobile phone is rated as 4.2 V , 5800 mAh. How much energy is stored in it when fully charged ?
  1. 43.8 kJ
  2. 48.7 kJ
  3. 87.7 kJ
  4. 24.4 kJ

Solution

Given $\mathrm{V}=4.2$ volt
$\therefore$ Energy supplied by battery
$=\mathrm{vq}=4.2 \times 5800 \times 3600 \times 10^{-3} \mathrm{~J}=87.696 \mathrm{~kJ}$
$\therefore$ Energy stored in the battery when fully charged
$=87.696 \mathrm{~kJ} \approx 87.7 \mathrm{~kJ}$

Asked in: JEE Main 2025 (02 Apr Shift 1)

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