A 12.5eV electron beam is used to bombard gaseous hydrogen at room temperature What series of wavelengths will be emitted.

If radiations of all wavelengths from ultraviolet to infrared is passed through hydrogen gas at room temperature, absorption lines will be observed in

(a) Using Bohr's second postulate of quantization of orbital angular momentum, show that the circumference of the electron in the nth orbital state in hydrogen atom is n times the de-Broglie wavelength associated with it. (b) The electron in hydrogen atom is initially in the third excited state. What is the maximum number of spectral lines which can be emitted when it finally moves to the ground state ?

What is the average electron thermal velocity at room temperature?

(a) Using Bohr's postulates, derive the expression for the total energy of the electron in the stationary states of the hydrogen atom. (b) Using Rydberg formula, calculate the wavelengths of the spectral lines of the first member of the Lyman series and of the Balmer series.

The figure shows the energy level of certain atom. When the electron deexcites from 3E to E, an electromagnetic wave of wavelength lamda is emitted. What is the wavelength of the electromagnetic wave emitted when the electron de excites from (5E)/(3) to E?

A baloon is filled with hydrogen at room temperature. It will burst if pressure exceeds 0.2 bar . If at 1 bar pressure the gases occupies 0.30 L volume , upto what volume can the balloon be expanded by filling H_(2)?