Question

In LCR circuit, the capacitance is changed from C to 4C. For the same resonant frequency, the inductance should be changed from L to

• A. 2L
• B. L/2
• C. L/4
• D. 4L

Answer 1

Answer: (C)

L/4

Answer 2

By using $\nu_{0} = \frac{1}{2\pi\sqrt{LC}}$ ⇒ $L \propto \frac{1}{C}$ ⇒ $\frac{L'}{L} = \frac{C}{C'} = \frac{C}{4C}$

⇒ $L' = \frac{L}{4}$.