Atoms Test - 51...

In an atom an electron excites to the fourth orbit. When it jumps back to the energy levels a spectrum is formed.Total number of spectral lines in this spectrum would be 

A proton, a direction ion and an $$\alpha$$-particle of equal kinetic energy perform circular motion normal to a uniform magnetic field $$B$$. If the radii of their paths are $$r_p, r_d$$ and $$r_\alpha$$ respectively then [Here, $$q_d = q_p, m_d = 2m_p$$]

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

The radius of first orbit of hydrogen atom is $$0.53\ A$$. The radius of its fourth orbit will be-

If in Bohr's atomic model, it is assumed that force between electron the proton varies inversely as $${r^4},$$b energy of the system will be proportional to:

If m is mass of electron, v its velocity, r the radius of stationary circular orbit around a nucleus with charge Ze then from Bohr's first postulate, the kinetic energy $$K=\dfrac{1}{2}mv^2$$ of the electron in C.G.S. system is equal to?

A Proton and an $$/alpha $$ particle are accelerated through a potential difference of 100V. The ratio of the wavelength associated with the proton to that associated with an $$/alpha $$ particle is

Electrons accelerated from rest by a potential difference of $$12.75V$$, are bombarded on a mono-atomic hydrogen gas. Possible emission of spectral lines are:-

A positroniuim  consists of an electron and a positron revolving about their common centre of mass. Calculate the kinetic energy of the electron in ground state:

The ground state energy of $$H$$- atom is $$-13.6eV$$. The energy needed to ionise $$H$$- atoms from its second excited state is: