The work function of a metal surface is 2 eV. When the light of frequency f is incident on the surface, the maximum kinetic energy of the photoelectrons emitted is 5 eV. If the frequency of the incident light is increased to 4f, then the maximum kinetic energy of the photoelectron emitted will be:

1.  20 eV

2.  22 eV

3.  26 eV

4.  28 eV

The variation of the kinetic energy \((K)\) of photoelectrons as a function of the frequency \((f)\) of the incident radiation is best shown by:

1.		2.
3.		4.

Light of a frequency of \(1.5\) times the threshold frequency is incident on a photosensitive material. What happens to the photoelectric current when the frequency is cut in half and the intensity is doubled?

An electron is accelerated from rest through a potential difference of \(V\) volt. If the de Broglie wavelength of an electron is $\mathrm{}$\(1.227\times10^{-2}~\text{nm}\). what will be its potential difference?
1. \(10^{2}~\text{V}\)
2. \(10^{3}~\text{V}\)
3. \(10^{4}~\text{V}\)
4. \(10^{5}~\text{V}\)

Light of wavelength 488 nm is produced by an argon laser which is used in the photoelectric effect. When light from this spectral line is incident on the emitter, the stopping (cut-off) potential of photoelectrons is 0.38 V. Find the work function of the material from which the emitter is made.

1. 2.16 eV
2. 3.06 eV
3. 2.0 eV
4. 0.38 eV

What will be the momentum, of the electrons accelerated through a potential difference of 56 V.
1. \(4.07 \times 10^{-25} \mathrm{~kg} \mathrm{~ms^{-1 }}\)
2. \(4.04 \times 10^{-24} \mathrm{~kg} \mathrm{~ms}^{-1}\)
3. \(4.07 \times 10^{-24} \mathrm{~kg} \mathrm{~ms^{-1 }}\)
4. \(4.04 \times 10^{-25} \mathrm{~kg} \mathrm{~ms}^{-1}\)

What is the de Broglie wavelength of an electron with the kinetic energy of \(120\) eV?
1. \(0.123\) nm
2. \(0.121\) nm
3. \(0.112\) nm
4. \(0.131\) nm

For what kinetic energy of a neutron will the associated de Broglie wavelength be
1.40 x ${10}^{-10}$ m?

1.\(1.1 \times 10^{-2}\ eV\)
2.\(2.1 \times 10^{-2}\ eV\)
3.\(3.3 \times 10^{-2}\ eV\)
4.\(4.2 \times 10^{-2}\ eV\)

What is the de Broglie wavelength of a nitrogen molecule in air at 300 K? Assume that the molecule is moving with the root-mean-square speed of molecules at this temperature. (Atomic mass of nitrogen = 14.0076 u)

1. 0.028 nm
2. 0.031 nm
3. 0.127 nm
4. 0.0139 nm

About \(5\)% of the power of a \(100\) W light bulb is converted to visible radiation. What is the average intensity of visible radiation at a distance of \(1\) m from the bulb?
1. \(0.472\) W/m²
2. \(0.398\) W/m²
3. \(0.323\) W/m²
4. \(0.401\) W/m²