Four lowest energy levels of H-atom are shown in the figure. The number of possible emission lines would be

(1) 3             

(2) 4

(3) 5             

(4) 6

The wavelength of light emitted when an electron jumps from second orbit to first orbits in a hydrogen atom is 
(a) $1.215\times {10}^{-7} \mathrm{m}$         (b) $1.215\times {10}^{-5} \mathrm{m}$
(c) $1.215\times {10}^{-4} \mathrm{m}$          (d) $1.215\times {10}^{-3} \mathrm{m}$

The de-Broglie wavelength of an electron in the first Bohr orbit is 

(1) Equal to one fourth the circumference of the first orbit

(2) Equal to half the circumference of the first orbit

(3) Equal to twice the circumference of the first orbit

(4) Equal to the circumference of the first orbit

The frequency of 1st line of Balmer series in ${\mathrm{H}}_2$ atom is ${\mathrm{v}}_0$. The frequency of line emitted by singly ionised He atom is

(1) 2${\mathrm{v}}_0$          

(2) 4${\mathrm{v}}_0$

(3) ${\mathrm{v}}_0$/2         

(4) ${\mathrm{v}}_0$/4

When the electron in the hydrogen atom jumps from 2nd orbit to 1st orbit, the wavelength of radiation emitted is $\mathrm{\lambda }$. When the electrons jump from 3rd orbit to 1st orbit, the wavelength of emitted radiation would be

 
(1) $\frac{27}{32}\mathrm{\lambda }$             

(2) $\frac{32}{27}\mathrm{\lambda }$

(3) $\frac{2}{3}\mathrm{\lambda }$               

(4) $\frac{3}{2}\mathrm{\lambda }$

Which of the following transition will have shortest emission wavelength ?

(1) n = 2 to n =1           

(2) n = 1 to n = 2 

(3) n = 2 to n = 5         

(4) n = 5 to n = 2 

If the binding energy of the electron in a hydrogen atom is 13.6 eV, the energy required to remove the electron from the first excited state of ${\mathrm{Li}}^{++}$ is 

(1) 122.4 eV       

(2) 30.6 eV

(3) 13.6 eV         

(4) 3.4 eV

Which state of triply ionised Beryllium $\left({\mathrm{Be}}^{+++}\right)$ has the same orbital radius as that of the ground state of hydrogen

(1) n = 4                 

(2) n = 3

(3) n = 2                 

(4) n = 1

The ratio of areas within the electron orbits for the first excited state to the ground state for hydrogen atom is

1. 16 : 1             

2. 18 : 1

3. 4 : 1               

4. 2 : 1

Taking Rydberg’s constant ${\mathrm{R}}_{\mathrm{H}}=1.097\times {10}^7 \mathrm{m}$ first and second wavelength of Balmer series in hydrogen spectrum is

(1) 2000 Å, 3000 Å                 

(2) 1575 Å, 2960 Å

(3) 6529 Å, 4280 Å                 

(4) 6552 Å, 4863 Å