Question

Figure shows an L-R circuit. When the switch $S$ is closed, the current through resistor $R_{1}, R_{2}$ and $R_{3}$ are $I_{1}, I_{2}$ and $I_{3}$ respectively. The value of $I_{1}, I_{2}$ and $I_{3}$ at $t=0 s$ is,

• A. $I_{1}=I_{2}=I_{3}=0$
• B. $I_{1}=\frac{E}{R_{1}}, I_{2}=I_{3}=0$
• C. $I_{1}=0, I_{2}=\frac{E}{R_{2}}, I_{3}=\frac{E}{R_{3}}$
• D. $I_{1}=\frac{E}{R_{1}}, I_{2}=\frac{E}{R_{2}+L_{1}}, I_{3}=\frac{E}{R_{3}+L_{3}}$

Answer 1

Answer: (B)

At $t=0$, inductor offers infinite resistance
So $, I_{1}=\frac{E}{R_{1}}, I_{2}=I_{3}=0$