Question

An ideal coil of $10\, H$ is joined in series with a resistance of $5 \,\Omega$ and battery of $5\, V,\, 2 s$ after joining the current flowing (in ampere) in the circuit will be

• A. ${{e}^{-1}}$
• B. $(1-{{e}^{-1}})$
• C. $(1-e)$
• D. $e$

Answer 1

Answer: (B)

$(1-{{e}^{-1}})$

Answer 2

Given, $L=10\, H,\, R=5 \Omega,\, E=5\, V$ and $t=2\, s$. Current in $R-L$ circuit $I=I_{0}\left(1-e^{-R t / L}\right)$ $I=\frac{E}{R}\left(1-e^{-R t / L}\right)$ $=\frac{5}{5}\left(1-e^{-5 \times 2 / 10}\right)$ $I=\left(1-e^{-1}\right)$