Question

Two resistance of $10\, \Omega$ and $20\, \Omega$ and an inductor of inductance $5\, H$ are connected to a battery of $2\, V$ through a key $K$ as shown in the figure. At time $t=0$ when the key $K$ is closed, the initial current through the battery is:

• A. $0.2 A$
• B. $\frac{2}{15} A$
• C. $\frac{1}{15} A$
• D. $0 A$

Answer 1

Answer: (C)

Initially the inductance will oppose the current which tries to flow through the inductance. But $10\, \Omega$ and $20\, \Omega$ can conduct. The current will be
According to ohm's law
$I=\frac{V}{R}=\frac{1}{30}=\frac{1}{15} A$