Question

In a $L-C$ circuit, $L=0.75\text{H}$ and $C=18\mu \text{F}$, at the instant when the current in the inductor is changing at a rate of $3.40\text{A/s}$. What is the charge on capacitor ?

• A. $26\mu \text{C}$
• B. $36\mu \text{C}$
  
• C. $46\mu \text{C}$
  
• D. $56\mu \text{C}$

Answer 1

The correct option is C $46\mu \text{C}$



On applying Kirchhoff's law starting from $A$,

$+\frac{q}{C}-L\frac{di}{dt}=0$

$\Rightarrow q=CL\frac{di}{dt}$

$=18\times {10}^{-6}\times 0.75\times 3.4$

$\approx 4.6\times {10}^{-5}\text{C}=46\mu \text{C}$

Hence, $\left(C\right)$ is the correct answer.