A double slit experiment is immersed in water of refractive index 1.33. The slit separationis 1 $$\mathrm{mm}$$ and the distance between slit and screen is $$1.33 \mathrm{~m}$$. The slits are illuminated by a light of wavelength $$6300\,\mathop A\limits^o $$. The fringewidth is

Two small drops of mercury each of radius '$$R$$' coalesce to form a large single drop. The ratio of the total surface energies before and after the change is

On a photosensitive surface, if the intensity of incident radiation is increased, the stopping potential

A particle executes linear S.H.M. The mean position of oscillation is at the principal axis of a convex lens of focal length $$8 \mathrm{~cm}$$. the mean position of oscillation is at 14 cm from the lens with amplitude 1 cm. The amplitude of oscillating image of the particle is nearly