QJEEM21Ph15ec: JEE Main 2021 Physics - Class 12 JEEM21Ph15ec Solution: The energy dissipated by a resistor is 10 mJ in 1 s when an…

Given, energy dissipated by a resistor, H = 10 mJ = 10 $\times$ 10 ^{$-$ 3} J

Time, t = 1 s

Electric current, I = 2 mA = 2 $\times$ 10 ^{$-$ 3} A

Resistance, R = ?

According to Joule's law of heating,

H = I²Rt

$\Rightarrow R = {H \over {{I^2}T}}$ ....... (i)

Substituting the given values in Eq. (i), we get

$R = {{10 \times {{10}^{ - 3}}} \over {{{(2 \times {{10}^{ - 3}})}^2} \times 1}}$

$\Rightarrow R = {{{{10}^{ - 2}}} \over {4 \times {{10}^{ - 6}}}} \Rightarrow R = 0.25 \times {10^4}$

$\Rightarrow R = 2500\,\Omega$