An unpolarised light beam of intensity $$2 I_{0}$$ is passed through a polaroid P and then through another polaroid Q which is oriented in such a way that its passing axis makes an angle of $$30^{\circ}$$ relative to that of P. The intensity of the emergent light is

An $$\alpha$$ particle and a proton are accelerated from rest through the same potential difference. The ratio of linear momenta acquired by above two particles will be:

An object of mass $$1 \mathrm{~kg}$$ is taken to a height from the surface of earth which is equal to three times the radius of earth. The gain in potential energy of the object will be [If, $$\mathrm{g}=10 \mathrm{~ms}^{-2}$$ and radius of earth $$=6400 \mathrm{~km}$$ ]

A ball is released from a height h. If $$t_{1}$$ and $$t_{2}$$ be the time required to complete first half and second half of the distance respectively. Then, choose the correct relation between $$t_{1}$$ and $$t_{2}$$.