QJEEM22Ph21cd: JEE Main 2022 Physics - Class 12 JEEM22Ph21cd Solution: A resistance of 40 is connected to a source of alternating…

$I = {I_0}\cos (\omega t)$ say

$\Rightarrow$ At maximum $\omega {t_1} = 0$ or ${t_1} = 0$

Then at rms value $I = {I_0}/\sqrt 2$

$\Rightarrow \omega {t_2} = \pi /4$

$\Rightarrow \omega ({t_2} - {t_1}) = \pi /4$

$\Delta t = {\pi \over {4\omega }} = {{\pi T} \over {4 \times 2\pi }}$

$= {1 \over {400}}s$ or 2.5 ms