Question

Time period of a block suspended from the upper plate of a parallel plate capacitor by a spring of stiffness k is T. When block is uncharged. If a charge q is given to the block them, the new time period of oscillation will be

• A. T
• B. >T
• C. <T
• D.

Answer 1

The correct option is A T

The forces that act on the block are qE and mg. Since qE and mg are constant forces, the only variable elastic force changes by kx. Where x is the elongation in the spring unbalanced (restoring) force = F= -kx

$\Rightarrow -m{w}^{2}X=-KX\Rightarrow w=\sqrt{\frac{k}{M}}$

The tim period of oscillation will remain the same