In Young's double slit experiment with light of wavelength $\lambda$, the intensity of light at a point on the screen where the path difference becomes $\frac{\lambda}{3}$ is ( $I$ is intensity of the central bright fringe)

A thin spherical shell of radius $R$ and surface charge density $\sigma$ is placed in a cube of side $5 R$ with their centers coinciding. The electric flux through one face of the cube is $\left(\varepsilon_0=\right.$ Permittivity of free space $)$

As shown in the figure, a dielectric of constant $K$ is placed between the plates of a parallel plate capacitor and is charged to a potential $V$ using a battery. If the dielectric is pulled out after disconnecting the battery from the capacitor, the final potential difference across the plates of the capacitor is

The drift speed of electrons in a material is found to be $0.3 \mathrm{~ms}^{-1}$ when an electric field of $2 \mathrm{Vm}^{-1}$ is applied across it. The electron mobility (in $\mathrm{m}^2 \mathrm{~V}^{-1} \mathrm{~s}^{-1}$ ) in the material is