Bob of a simple pendulum of length $l$ is made of iron . The pendulum is oscillating over a horizontal coil carrying direct current. If the time period of the pendulum is $T$ then
Bob of a simple pendulum of length $l$ is made of iron . The pendulum is oscillating over a horizontal coil carrying direct current. If the time period of the pendulum is $T$ then
- [JEE MAIN 2013]
- A
$T < 2\pi \sqrt {\frac{l}{g}} $ and damping is smaller than in air alone.
- B
$T = 2\pi \sqrt {\frac{l}{g}} $ and damping is larger than in air alone.
- C
$T > 2\pi \sqrt {\frac{l}{g}}$ and damping is smaller than in air alone.
- D
$T < 2\pi \sqrt {\frac{l}{g}} $ and damping is larger than in air alone
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