An $\alpha -$particle of energy 5 MeV is scattered through $180°$ by a fixed uranium nucleus. The distance of closest approach is of the order

1. ${10}^{-10}<mspace\; width="1em"></mspace>m$ 

2. ${10}^{-13}<mspace\; width="1em"></mspace>m$ 

3. ${10}^{-14}<mspace\; width="1em"></mspace>m$ 

4. ${10}^{-16}<mspace\; width="1em"></mspace>m$

In the Rutherford scattering experiment, what will be the correct angle for $\propto$-scattering for an impact parameter, b = 0?

1. ${90}^{\circ }$

2. ${270}^{\circ }$

3. $0^{\circ }$ 

4. ${180}^{\circ }$

The velocity of the electron in the ground state (H - atom) is 

1. $2.18\times {10}^5<mspace\; width="1em"></mspace>m/s$   

2. $2.18\times {10}^6<mspace\; width="1em"></mspace>m/s$

3. $2.18\times {10}^7<mspace\; width="1em"></mspace>m/s$   

4. $2.18\times {10}^8<mspace\; width="1em"></mspace>m/s$

When a hydrogen atom is raised from the ground state to excited state

1. both KE and PE increase

2. both KE and PE decrease

3. PE increases and KE decreases

4. PE decreases and KE increases

The ionisation potential of helium atom is 24.6 volt, the energy required to ionise it will be

1. 24.6 eV 

2. 24.6 volt 

3. 13.6 volt 

4.13..6 eV

In an experiment to determine the e/m value for an electron using Thomson's method the electrostatic deflection plates were 0.01 m apart and had a potential difference of 200 volts applied. Then the electric field strength between the plates is 

1. $1\times {10}^4<mspace\; width="1em"></mspace>V/m$ 

2. $2\times {10}^4<mspace\; width="1em"></mspace>V/m$

3. $4\times {10}^4<mspace\; width="1em"></mspace>V/m$ 

4. $5\times {10}^5<mspace\; width="1em"></mspace>V/m$

An alpha nucleus of energy $\frac{1}{2}m{v}^2$ bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to

(a) $\frac{1}{Ze}$                              (b) $v^2$

(c) $\frac{1}{m}$                               (d) $\frac{1}{v^4}$

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?

The ratio of momenta of an electron and an $\mathrm{}$\(\alpha \text-\)particle which are accelerated from rest by a potential difference of \(100~\text{V}\) is:
1. \(1\)
2. \(\sqrt{\frac{2m_e}{m_{\alpha}}}\)
3. \(\sqrt{\frac{m_e}{m_{\alpha}}}\)
4. \(\sqrt{\frac{m_e}{2m_{\alpha}}}\)

The fact that electric charges are integral multiples of the fundamental electronic charge was proved experimentally by 
(1) Planck                   

(2) J.J. Thomson

(3) Einstein                 

(4) Millikan