Two sources of light $$0.6 \mathrm{~mm}$$ apart and screen is placed at a distance of $$1.2 \mathrm{~m}$$ from them. A light of wavelength $$6000\,\mathop A\limits^o$$ used. Then the phase difference between the two light waves interfering on the screen at a point at a distance $$3 \mathrm{~mm}$$ from central bright band is

The ratio of longest to shortest wavelength emitted in Paschen series of hydrogen atom is

The height of liquid column raised in a capillary tube of certain radius when dipped in liquid '$$A$$' vertically is $$5 \mathrm{~cm}$$. If the tube is dipped in a similar manner in another liquid '$$B$$' of surface tension and density double the values of liquid '$$A$$', the height of liquid column raised in liquid '$$B$$' would be (Assume angle of contact same)

A particle of mass '$$\mathrm{m}$$' is rotating along a circular path of radius '$$r$$' having angular momentum '$$L$$'. The centripetal force acting on the particle is given by