A monochromatic ray of light is incident normally on a thin prism of refracting angle A . The ray is deviated through an angle $(1.15)^{\circ}$ in passing through the prism. The ray reflected internally from the second face emerges from the first face making an angle of $(6.3)^{\circ}$ with the incident ray. The refractive index of the prism is

The wavelength ' $\lambda$ ' of a photon and the deBroglie wavelength of an electron have same value. the ratio of kinetic energy of the electron to the energy of a photon is

( $\mathrm{m}=$ mass of electron, $\mathrm{c}=$ velocity of light, $\mathrm{h}=$ Planck's constant)

The heat energy that must be supplied to 14 gram of nitrogen at room temperature to raise its temperature by $48^{\circ} \mathrm{C}$ at constant pressure is (Molecular weight of nitrogen $=28, R=$ gas constant, $\mathrm{C}_{\mathrm{p}}=\frac{7}{2} \mathrm{R}$ for diatomic gas)

Charges of $2 \mu \mathrm{C}$ and $-3 \mu \mathrm{C}$ are placed at two points A and B separated by distance of 1 m . The distance of the point from $A$ where net potential is zero is