In terms of Rydberg's constant R, the wave number of the first Balmer line is 
(1) R               

(2) 3R

(3) $\frac{5\mathrm{R}}{36}$         

(4) $\frac{8\mathrm{R}}{9}$

The absorption transitions between the first and the fourth energy states of hydrogen atom are 3. The emission transitions between these states will be 
1. 3             

2. 4

3. 5             

4. 6

In Bohr's model of hydrogen atom, let PE represents potential energy and TE the total energy. In going to a higher level 

(1) PE decreases, TE increases

(2) PE increases, TE increases

(3) PE decreases, TE decreases

(4) PE increases, TE decreases

 According to Bohr's model, the radius of the second orbit of helium atom is 
(1) 0.53 Å             

(2) 1.06 Å

(3) 2.12 Å             

(4) 0.265 Å

An ionic atom equivalent to hydrogen atom has wavelength equal to 1/4 of the wavelengths of hydrogen lines. The ion will be 
(1) ${\mathrm{He}}^{+}$        

(2) ${\mathrm{Li}}^{++}$

(3) ${\mathrm{Ne}}^{9+}$       

(4) ${\mathrm{Na}}^{10+}$

The first line of Balmer series has wavelength 6563 Å. What will be the wavelength of the first member of Lyman series

(1) 1215.4 Å             

(2) 2500 Å

(3) 7500 Å               

(4) 600 Å

 For electron moving in ${\mathrm{n}}^{\mathrm{th}}$ orbit of H-atom the angular velocity is proportional to 
(1) n                       

(2) 1/n

(3) ${\mathrm{n}}^3$                    

(4) 1/${\mathrm{n}}^3$

In Bohr model of hydrogen atom, the ratio of periods of revolution of an electron in n =2 and n = 1 orbits is

(1) 2 : 1             

(2) 4 : 1

(3) 8 : 1             

(4) 16 : 1

The first line in the Lyman series has wavelength $\mathrm{\lambda }$. The wavelength of the first line in Balmer series is

(1) $\frac{2}{9}\mathrm{\lambda }$             

(2) $\frac{9}{2}\mathrm{\lambda }$
(3) $\frac{5}{27}\mathrm{\lambda }$           

(4) $\frac{27}{5}\mathrm{\lambda }$

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