Atoms Test - 80...

A hydrogen atom, initially in the ground state is excited by absorbing a photon of wavelength $$980\mathring { A } .$$ The radius of the atom in excited state, in terms of Bohr radius a, will be:
$$\left( hc=12500\quad eV-\mathring { A }  \right) $$

The time taken by the electron in one complete revolution in the $$n^{th}$$ Bohr's orbit of the hydrogen atom is 

The ratio of frequencies of the first line of the lyman series and the first line of blamer series is 

Hydrogen atoms in a sample are excited to $$n=5$$ state and it is found that photons of all possible wavelengths are present in the emission spectra. The minimum number of hydrogen atoms in the sample would be

The radius of the orbital of electron in the hydrogen atom is $$ 0.5 A^0 $$ . the speed of the electron is $$ 2 \times 10^5 m/s $$. then, the current in the loop due to the motion of the electron is 

Suppose, the electron in a hydrogen atom makes transition from $$n = 3$$ to $$n = 2$$ in $$10^{-8}$$s. The order of the torque acting on the electron in this period, using the relation between torque and angular momentum as discussed in the chapter on rotational mechanics is

In an atom two electrons move round the nucleus in circular orbits of radii R and $$4R$$ respectively. The ratio of the time taken by them to complete one revolution is?

The radius of the shortest orbit in a  one-electron system is 18 pm. It may be

In hydrogen atom, electron revolves around nucleus in circular orbit of radius $$5 \times 10 ^{- 11}\, m$$ at a speed $$2.2 \times 10^6 m/s$$. Then the orbital current will be: 

The minimum orbital angular momentum of the electron in a hydrogen atom is