K.E. of the electron is 4.55 x 10^-25 J. Its de Broglie wave length is ...

The wavelength associated with a golf ball weighing 200g and moving at a speed of 5m/h is of the order.

The ratio of wave length of photon corresponding to the alpha-line of Lyman series in H-atom and Beta-line of Balmer series in He+ is