51.A wave in which the particles of the material move up and down as the wave goes from left to right is known as :

52.A glass tumbler containing ice shows droplets of water on the outer surface because :

53.Which one of the following is the correct arrangement in the decreasing order of the refractive indices of glass, diamond and water ?

54.The Moon is revolving in a circular orbit around Earth with a unifrom speed V. If the gravitational force suddenly disapperars, the Moon will :

55.A lighted candle gets extinguished when convered with a tumbler because of :