In biprism experiment, 21 fringes are observed in a given region using light of wavelength 4800 $$\mathop A\limits^o $$. If light of wavelength 5600 $$\mathop A\limits^o $$ is used, the number of fringes in the same region will be

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

In a single slit diffraction pattern, the distance between the first minimum on the left and the first minimum on the right is $$5 \mathrm{~mm}$$. The screen on which the diffraction pattern is obtained is at a distance of $$80 \mathrm{~cm}$$ from the slit. The wavelength used is 6000 $$\mathop A\limits^o $$. The width of the silt is

In Young's double slit experiment, with a source of light having wavelength $$6300 \mathop A\limits^o$$, the first maxima will occur when the