Question

An ideal inductor is connected in series with a resistor and an ideal battery. The battery supplies energy at a rate P(t), the resistor dissipates energy at a rate $P_R\left(t\right)$, and the inductor stores energy at a rate $P_L\left(t\right)$. What can be concluded about the relationship between $P_R\left(t\right)$ and $P_L\left(t\right)$?

• A. $P_R\left(t\right)>P_L\left(t\right)$ for all times t while charging
• B. $P_R\left(t\right)=P_L\left(t\right)$ for some value of t while charging
• C. $P_R\left(t\right)>P_L\left(t\right)$ only near the beginning of the charging
• D. $P_R\left(t\right)<P_L\left(t\right)$ only near the beginning of the charging

Answer 1

Answer: (B), (D)

The correct options are
B

$P_R\left(t\right)=P_L\left(t\right)$ for some value of t while charging

D

$P_R\left(t\right)<P_L\left(t\right)$ only near the beginning of the charging

The inductor behaves like infinite resistance at the beginning storing more energy than dissipated by the resistor which gradually decreases and energy dissipated by the resistor increases.