Stopping Potential Revisited

Q. The light of two different frequencies whose photons have energies $3.8\text{eV}$ and $1.4\text{eV}$ respectively, illuminate a metallic surface whose work function is $0.6\text{eV}$ successively. The ratio of maximum speeds of emitted electrons for the two frequencies respectively will be

1. $1:1$
2. $4:1$
3. $2:1$
4. $1:4$

Q.

If the energy of a photon corresponding to a wavelength of $6000\stackrel{\circ }{A}is3.32\times {10}^{-19}J$, the photon energy for a wavelength of $4000\stackrel{\circ }{A}$ will be

1. 1.6 eV

2. 1.4 eV

3. 4.9 eV

4. 3.1 eV

Q.

Light of wavelength $1824\stackrel{\circ }{A}$, incident on the surface of a metal, produces photo-electrons with maximum energy 5.3 eV. When light of wavelength $1216\stackrel{\circ }{A}$ is used, the maximum energy of photoelectrons is 8.7 eV. The work function of the metal surface is

1. 13.6 eV

2. 6.8 eV

3. 3.5 eV

4. 1.5 eV

Q.

A metal surface of work function 1.07 eV is irradiated with light of wavelength 332 nm. The retarding potential required to stop the escape of photo-electrons is

1. 2.66 eV

2. 3.74 eV

3. 1.07 eV

4. 4.81 eV

Q.

The work function of metal is 1 eV. Light of wavelength $3000\stackrel{\circ }{A}$ is incident on this metal surface. The velocity of emitted photo-electrons will be

1. $10m/sec$

2. $1\times {10}^{3}m/sec$

3. $1\times {10}^{4}m/sec$

4. $1\times {10}^{6}m/sec$

Q.

The light rays having photons of energy 1.8 eV are falling on a metal surface having a work function 1.2 eV. What is the stopping potential to be applied to stop the emitting electrons

1. 3 eV

2. 1.2 eV

3. 0.6 eV

4. 1.4 eV

Q.

The retarding potential for having zero photo-electron current

1. Increases uniformly with the increase in the wavelength of incident light

2. Is proportional to the frequency of incident light

3. Increases uniformly with the increase in the frequency of incident light wave

4. Is proportional to the wavelength of incident light

Q.

Ultraviolet radiations of 6.2 eV falls on an aluminium surface (work function 4.2 eV). The kinetic energy in joules of the fastest electron emitted is approximately

1. $3.2\times {10}^{-21}$

2. $3.2\times {10}^{-19}$

3. $3.2\times {10}^{-15}$

4. $3.2\times {10}^{-17}$

Q. Light of wavelength $4000\stackrel{\circ }{A}$ falls on a photosensitive metal and a negative 2V potential stops the emitted electrons. The work function of the material (in eV) is approximately $(h=6.6\times {10}^{-34}Js,e=1.6\times {10}^{-19}C,c=3\times {10}^{8}m{s}^{-1})$

1. 2.2
2. 1.1
3. 2
4. 3.1

Q.

Stopping potential for photoelectrons

1. Does not depend on the frequency of the incident light

2. Does not depend upon the nature of the cathode material

3. Depends on both the frequency of the incident light and nature of the cathode material

4. Depends upon the intensity of the incident light