Mean free path of molecules in a polyatomic gas is independent of

Three masses $700 \mathrm{~g}, 500 \mathrm{~g}$ and 400 g are suspended at the end of a spring shown in figure and are in equilibrium. When the 700 g mass is removed, the system oscillates with a time period of 3 s . If 500 g mass is further removed, then it will oscillate with a period of

A thin prism of angle $6^{\circ}$ made of glass of refractive index 1.5 is combined with another prism made of refractive index 1.75 to produce dispersion without deviation. Then, the angle of the second prism is

A small object is placed in the air, at a distance 45 cm from a convex refracting surface of radius of curvature 15 cm . If the surface separates air from glass of refractive index 1.5, then the position of image is