What is the de-Broglie wavelength associated with an electron accelerated through a voltage of 900 V?

1.  $0.31$ $\stackrel{\mathrm{o}}{\mathrm{A}}$ $$ $$

2.  $0.41$ $\stackrel{\mathrm{o}}{\mathrm{A}}$ $$

3.  $0.5$ $\stackrel{\mathrm{o}}{\mathrm{A}}$ $$ $$

4.  $0.16$ $\stackrel{0}{\mathrm{A}}$

A particle of mass M at rest decays into two masses   \(m_{1}\) and \(m_{1}\)  having non-zero velocities. What will be the ratio of their de-Broglie wavelengths?

What is the de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature T (Kelvin) and mass m?

1. $\frac{h}{\sqrt{mkT}}$

2. $\frac{h}{\sqrt{3mkT}}$

3. $\frac{2h}{\sqrt{3mkT}}$ $$

4. $\frac{2h}{\sqrt{mkT}}$

If an electron of mass m with a de-Broglie wavelength of \(\lambda\) falls on the target in an X-ray tube, the cut-off wavelength ( λ₀) of the emitted X-ray will be:

1. ${\lambda }_0=\frac{2mc{\lambda }^2}{h}$         

2. ${\lambda }_0=\frac{2h}{mc}$

3. ${\lambda }_0=\frac{2m^2{c}^2{\lambda }^3}{h^2}$       

4. ${\lambda }_0=\lambda$

Photons with energy 5 eV are incident on a cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C, no photoelectron will reach the anode A, if the stopping potential of A relative to C is:

1. +3 V

2. +4 V

3. - 1V

4. -3 V

A certain metallic surface is illuminated with monochromatic light of wavelength λ. The stopping potential for photoelectric current for this light is 3V_o. If the same surface is illuminated with light of wavelength 2λ, the stopping potential is V_o. The photoelectric effect's threshold wavelength for this surface is?

1. 6λ

2. 4λ

3. λ/4

4. λ/6

Which of the following figures represents the variation of the particle momentum and the associated de-Broglie wavelength?

1.		2.
3.		4.

A photoelectric surface is illuminated successively by monochromatic light of wavelengths λ and λ/2. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface of the material will be:
(h = Planck’s constant, c = speed of light)

1. hc/2λ

2. hc/λ

3. 2hc/λ

4. hc/3λ

Light with a wavelength of 500 nm is incident on a metal with a work function of 2.28 eV. The de Broglie wavelength of the emitted electron will be:
1. \( <2.8 \times 10^{-10} \mathrm{~m} \)
2. \( <2.8 \times 10^{-9} \mathrm{~m} \)
3. \( \geq 2.8 \times 10^{-9} \mathrm{~m} \)
4. \( <2.8 \times 10^{-12} \mathrm{~m}\)

When the energy of the incident radiation is increased by 20%, the kinetic energy of the photoelectrons emitted from a metal surface increases from 0.5 eV to 0.8 eV. The work function of the metal will be:
1. 0.65 eV

2. 1.0 eV

3. 1.3 eV

4. 1.5 eV