Question

A hemisphere of radius R is placed in a uniform electric field E parallel to the axis of the hemisphere. If the lines of E enter through the hollow part (flat base) of the hemisphere, then the flux ${\psi }_E$ is

• A. zero
• B. $\pi R^{2}E$
• C. $1/2\pi R^{2}E$
• D. $2\pi R^{2}E$

Answer 1

Answer: (B)

$\pi R^{2}E$

By Gauss's law, the flux ${\psi }_E=E\times$ area of flat base $=E\times \pi R^2=\pi R^{2}E$