In a Rutherford scattering experiment when a projectile of charge \(Z_1\) and mass \(M_1\) approaches a target nucleus of charge \(Z_2\)
 and mass \(M_2\) the distance of the closest approach is \(r_0.\) What is the energy of the projectile?

1.	Directly proportional to \(M_1 \times M_2\)
2.	Directly proportional to \(Z_1Z_2\)
3.	Inversely proportional to \(Z_1\)
4.	Directly proportional to the mass \(M_1\)

The ionization energy of the electron in the hydrogen atom in its ground state is 13.6 eV. The atoms are excited to higher energy levels to emit radiations of 6 wavelengths. Maximum wavelength of emitted radiation corresponds to the transition between

1. n=3 to n=2 states

2. n=3 to n=1 states

3. n=2 to n=1 states

4. n=4 to n=3 states

The ground state energy of hydrogen atom is -13.6 eV. When its electron is in the first excited state, its excitation energy is:

1. 3.4 eV                               

2. 6.8 eV

3. 10.2 eV                             

4. zero 

In the phenomenon of electric discharge through gases at low pressure, the coloured glow in the tube appears as a result of:

1. excitation of electrons in the atoms 

2. the collision between the atoms of the gas 

3. the collisions between the charged particles emitted from the cathode and the atoms of the gas 

4. the collision between different electrons of the atoms of the gas 

According to de-Broglie, the de-Broglie wavelength for electron in an orbit of hydrogen atom is ${10}^{-10}$ m. The principle quantum number for this electron is $\left(r=5.13\times {10}^{-11}m\right)$
(a) 1           (b) 2
(c) 3           (d) 4

If in nature there may not be an element for which the principal quantum number n > 4, then the total possible number of elements will be

(1) 60                   

(2) 32

(3) 4                     

(4) 64

In the \(n^{th}\) orbit, the energy of an electron is \(E_{n}=-\frac{13.6}{n^2} ~\text{eV}\) for the hydrogen atom. What will be the energy required to take the electron from the first orbit to the second orbit?
1. \(10.2~\text{eV}\)
2. \(12.1~\text{eV}\)
3. \(13.6~\text{eV}\)
4. \(3.4~\text{eV}\)

The Lyman series of hydrogen spectrum lies in the region

(1) Infrared               

(2) Visible

(3) Ultraviolet             

(4) X- rays

Which one of the series of hydrogen spectrum is in the visible region 

1. Lyman series             

2. Balmer series

3. Paschen series           

4. Bracket series

The Rutherford $\mathrm{\alpha }$-particle experiment shows that most of the $\mathrm{\alpha }$-particles pass through almost unscattered while some are scattered through large angles. What information does it give about the structure of the atom 

(1) Atom is hollow

(2) The whole mass of the atom is concentrated in a small centre called nucleus

(3) Nucleus is positively charged

(4) All the above