The radius of the first permitted Bohr orbit for the electron in a hydrogen atom is 0.5 Å, and its ground state energy is \(-13.6~\text{eV}.\) If the electron in the hydrogen atom is replaced by a muon \((\mu^{-}),\) which has the same charge as the electron but is \(207\) times more massive, what will be the new values for the first Bohr radius and ground state energy?

1.	\(0.53\times10^{-13}~\text{m}, ~-3.6~\text{eV}\)
2.	\(25.6\times10^{-13}~\text{m}, ~-2.8~\text{eV}\)
3.	\(2.56\times10^{-13}~\text{m}, ~-2.8~\text{keV}\)
4.	\(2.56\times10^{-13}~\text{m}, ~-13.6~\text{eV}\)

An electron in Bohr's hydrogen atom has angular momentum $\frac{2h}{\mathrm{\pi }}$. The energy of the electron is 

1.  -3.4 eV

2.  -0.64 eV

3.  -0.85 eV

4.  -10.25 eV

If the energy of the electron in an \(\mathrm{H}\)-atom in the ground state is taken to be \(-13.6\) eV, then the kinetic energy of the electron in the first excited state will be:
1. \(3.4\) eV
2. \(6.8\) eV
3. \(10.2\) eV
4. \(13.6\) eV

An electron and a proton are separated by a large distance. The electron starts approaching the proton with energy 2eV. The proton captures the electron and forms a hydrogen atom in first excited state. The resulting photon is incident on a photosensitive metal of threshold wavelength 4600Å. The maximum K.E. of the emitted photoelectron is (Take hc = 12420 eV Å)

1. 2.4 eV                     

2. 2.7 eV                     

3. 2.9 eV                         

4. 5.4 eV

The radius of Germanium \((\mathrm{Ge})\) nuclide is measured to be twice the radius of \({}_{4}^{9}\mathrm{Be}.\) The number of nucleons in \(\mathrm{Ge}\) is:
1. \(73\)
2. \(74\)
3. \(75\)
4. \(72\)

In a discharge tube ionization of enclosed gas is produced due to collisions between:

1. positive ions and neutral atoms/molecules

2. negative electrons and neutral atoms/molecules

3. photons and neutral atoms/molecules

4. neutral gas atoms/molecules