A simple pendulum has a length $\ell ,$ mass of bob $m.$ The bob is given a charge $q$ coulomb. The pendulum is suspended to a uniform horizontal electric field of strength $E$ as shown in the figure, then calculate the time period of oscillation when the bob is slightly displaced from its mean position is:

Charge $2Q$ and $-Q$ are placed as shown in figure. The point at which electric field intensity is zero will be:

The linear charge density on upper half of a segment of ring is $\lambda$ and at lower half, it is $-\lambda .$ The direction of electric field at centre $O$ of ring is:

Three large parallel plates have uniform surface charge densities as shown in the figure. Find out electric field intensity at point $P.$