An electron in the hydrogen atom jumps from nth excited state to the ground state. The wavelength so emitted illuminates a photosensitive material having work function 2.75 eV. If the stopping potential of the photo-electron is 10V, the value of n is 

(1) 3

(2) 4

(3) 5

(4) 2

When neutron moving with Kinetic Energy 2eV collides with 

stationary $H_1^1$ in the ground state, the collision will be:

1.  Must be elastic

2.  may be inelastic

3.  Both

4.  Must be perfectly inelastic

The energy of a hydrogen atom in its ground state is —13.6 eV. The energy of the level corresponding to the quantum number n = 2 (first excited state) in the hydrogen atom is:

1. -2.72 eV

2. - 0.85 eV

3. -0.54 eV

4. — 3.4 eV

When the electron of a hydrogen-like atom jumps from a higher energy level to a lower energy level, then,

1.  the angular momentum of the electron remains constant.

2.  the kinetic energy of the electron increases.

3.  the wavelength of the de-Broglie wave associated with the motion of the electron increases.

4.  the potential energy increases.

Which of the following transition in a hydrogen atom will produce radiations of minimum wavelength?

1.  n = 2 to n = 1

2.  n = 5 to n = 3

3.  n = 10 to n = 5

4.  n = 10 to n = 3

If an electron in an hydrogen atom jumps from an orbit $n_i=3$ to an orbit with level $n_f=2$, the frequency of the emitted radiation is 

1. $v=\frac{36 C}{5 R}$ 

2. v = $\frac{CR}{6}$

3. v = $\frac{5 RC}{36}$

4. v  = $\frac{6 C}{R}$

The energy of ground electronic state of hydrogen atom is -13.6 eV.  The energy of the first excited state will be [1997]

1. -54.4 eV 

2. -27.2 eV

3. -6.8 eV 

4. -3.4 eV

Energy E of a hydrogen atom with principal quantum number n is given by $E=\frac{-13.6}{n^2}eV$.  The energy of a photon ejected when the electron jumps from n = 3 state to n = 2 state of hydrogen, is approximately [2004]

1. 1.5 eV 

2. 0.85 eV 

3. 3.4 eV 

4. 1.9 eV

          
1. \(\frac{\lambda}{3}\)
2. \(\frac{3\lambda}{4}\)
3. \(\frac{4\lambda}{3}\)
4. \(3\lambda\)

The ground state energy of H-atom is 13.6 eV. The energy needed to ionise H-atom from its second excited state [1991]

1. 1.51 eV

2. 3.4 eV

3. 13.6 eV

4. 12.1 eV