Physics

The oil in the wick of an oil lamp rises up due to capillary action. This effect is due to surface tension of liquids. The wick here acts as a capillary tube

In superconductors, the energy gap is due to electron-phonon interaction.

The weight of the man mg is acting on the floor. As the lift is moving up with an acceleration, say a, the man too in it is having this acceleration. The force producing this acceleration is ma. By Newton’s third law, this force will have an equal reaction pressing the floor equal to ma. Therefore the total resultant reaction on the floor is mg+ma = m(g+a) which is mg, the weight of the man. So (a) is correct.

The friction between sand and feet is less than that between concrete and feet.

Light travels in a straight line (rectilinear propagation of light). This statement does hold if the medium of travel for light is homogeneous and transparent.