Consider 3^rd orbit of He⁺ (Helium), using non-relativistic approach, the speed of electron in this orbit will be (given Z = 2 and h (Planck's constant)= 6.6 x 10^-34 J-s)

1. 2.92 x10⁶ m/s
2. 1.46 x10⁶ m/s
3. 0.73 x10⁶ m/s
4. 3.0 x10⁸ m/s

The hydrogen gas with its atoms in the ground state is excited by monochromatic radiation of λ = 975 Å. The number of spectral lines in the resulting spectrum emitted will be :

1. 3

2. 2

3. 6

4. 10

Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelengths ${\mathrm{\lambda }}_1:{\mathrm{\lambda }}_2$ emitted in the two cases is

1. 7/5

2. 20/7

3. 27/5

4. 27/20

An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be 
(m is the mass of hydrogen atom, R is Rydberg constant and h is Plank’s constant)

1. $\frac{24m}{25hR}$

2. $\frac{25hR}{24m}$

3. $\frac{25m}{24hR}$

4.$\frac{24hR}{25m}$

The energy of a hydrogen atom in the ground state is -13.6eV. The energy of a He⁺ ion in the first excited state will be-

1. -13.6 eV

2. -27.2 eV

3. -54.4 eV

4. -6.8 eV

The total energy of electron in the ground state of hydrogen atom is -13.6 eV. The kinetic energy of an electron in the first excited state is:

1. 3.4 eV

2. 6.8 eV

3. 13.6 eV

4. 1.7 eV