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

The work function of cesium metal is \(2.14\) eV. When light of frequency \(6\times10^{14}\) Hz is incident on the metal surface, photoemission of electrons occurs. What is the stopping potential of the metal?
1. \(0.212\) V
2. \(0.345\) V
3. \(0.127\) V
4. \(0.311\) V

In an experiment on the photoelectric effect, the slope of the cut-off voltage versus frequency of incident light is found to be $4.12\times {10}^{-15} V s$. The value of Planck's constant is:

1. $6.682\times {10}^{-4} Js$
2. $6.592\times {10}^{-34} Js$
3. $6.621\times {10}^{-34} Js$
4. $6.502\times {10}^{-4} Js$

The threshold frequency for a certain metal is $3.3\times {10}^{14} \mathrm{Hz}.$ If the light of frequency $8.2\times {10}^{14} \mathrm{Hz}$ is incident on the metal, the cut-off voltage for the photoelectric emission is:

1. 1.1210 V.
2. 2.0292 V.
3. 3.8651 V.
4. 4.0832 V.

Light of frequency $7.21\times {10}^{14} \mathrm{Hz}$ is incident on a metal surface. Electrons with a maximum speed of $6.0\times {10}^5 \mathrm{m}/\mathrm{s}$ are ejected from the surface. What is the threshold frequency for the photoemission of electrons?

1. \(5.109 \times10^{14}\) Hz
2. \(3.45 \times10^{14}\) Hz
3. \(6.733 \times10^{14}\) Hz
4. \(4.738 \times10^{14}\) Hz

Ultraviolet light of wavelength 2271 Å from a 100 W mercury source irradiates a photocell made of molybdenum metal. If the stopping potential is −1.3 V, the work function of the metal is:

1. 4.15 eV
2. 3.01 eV
3. 1.30 eV
4. 2.12 eV

Monochromatic radiation of wavelength 640.2 nm (1 nm = 10^-9 m) from a neon lamp irradiates photosensitive material made of cesium on tungsten. The stopping voltage is measured to be 0.54 V. The source is replaced by an iron source and its 427.2 nm line irradiates the same photo-cell. The new stopping voltage is:

1. 0.54 eV
2. 1.3 eV
3. 1.5 eV
4. 1.63 eV

Light of intensity 10^-5 W m^-2 falls on a sodium photo-cell of surface area 2 cm². Assuming that the top 5 layers of sodium absorb the incident energy, The time required for photoelectric emission in the wave-picture of radiation is: (The work function for the metal is given to be about 2 eV.)

1. 0.2 year
2. 0.3 year
3. 0.4 year
4. 0.5 year