GATE 2026 IN – Question 16

Correct answer: (D) Band-stop filter

Explanation

The output is across the series LC branch, whose impedance is $Z_{LC}=j(\omega L-1/(\omega C))$. The voltage divider gives $V_{out}/V_{in}=Z_{LC}/(R+Z_{LC})$.

At $\omega_0=1/\sqrt{LC}$, $Z_{LC}=0$ and the output vanishes. At very low and very high frequencies, $|Z_{LC}|$ is large and the output approaches the input.

The circuit rejects frequencies near resonance and passes frequencies on either side: **band-stop filter (D)**.