4. The depletion layer in the p−n junction region is caused by ?

3. Ratio of intensities of two waves are given by 4 : 1. Then the ratio of the amplitudes of the two waves is ?

9. A beam of monochromatic light is refracted from vacuum into a medium of refractive index 1.5, the wavelength of refracted light will be ?

8. Green light of wavelength 5460 Å is incident on an air-glass interface. If the refractive index of glass is 1.5 , the wavelength of light in glass would be (c = 3 × $10^8$ $ms^−1$) ?

When air is replaced by a dielectric medium of force constant K, the maximum force of attraction between two charges, separated by a distance ___ ?

Physical independence of force is a consequence of