A metallic surface is exposed to two radiations separately, one of wavelength 4000 Å and the other of 8000 Å. If the work function of metal is 1 eV, then the ratio of maximum kinetic energies of photoelectrons is nearly equal to:
1. | \(\frac{32}{11} \) | 2. | \(\frac{42}{11} \) |
3. | \(\frac{52}{11} \) | 4. | \(\frac{62}{11}\) |
The figure shows the variation in photoelectric current (i) with voltage (V) between the electrodes in a photocell for two different radiations. If Ia and Ib are the intensities of the incident radiation and and their respective frequencies, then:
1. | \(I_a>I_b, \nu_b<\nu_a\) | 2. | \(I_a<I_b, \nu_b>\nu_a\) |
3. | \(I_a>I_b, \nu_b=\nu_a\) | 4. | \(I_a<I_b, \nu_b<\nu_a\) |
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
When a point source of monochromatic light is at a distance of 0.2 m from a photoelectric cell, the cut-off voltage and saturation current are 0.6 volts and 18 mA respectively. What will happen if the same source is placed 0.6 m away from the photoelectric cell?
1. | the stopping potential will be 0.2 volts. |
2. | the stopping potential will be 0.6 volts. |
3. | the saturation current will be 6 mA. |
4. | the saturation current will be 18 mA. |
The de-Broglie wavelength of an electron is the same as that of a photon of wavelength λ. If the mass of an electron is m, then its kinetic energy will be:
1.
2.
3.
4.
The variation of kinetic energy \((K)\) of photoelectrons as a function of frequency \((f)\) of the incident radiation is best shown by:
1. | 2. | ||
3. | 4. |
The correct graph between the maximum energy of a photoelectron and the inverse of the wavelength of the incident radiation is given by the curve:
1. | A | 2. | B |
3. | C | 4. | None of these |
If alpha, beta and gamma rays carry the same momentum, which has the longest wavelength?
1. | Alpha rays | 2. | Beta rays |
3. | Gamma rays | 4. | None, all have same wavelength |
The stopping potential of a photosensitive material is \(4~V\) when the wavelength of incident monochromatic radiation is \(\lambda.\) If the wavelength of incident radiation is doubled on the same photosensitive material, the stopping potential becomes \(V.\) The threshold wavelength of the photosensitive material will be:
1.
2.
3.
4.
When monochromatic photons of wavelength \(4000\) Å are incident on the metal plate of work function \(2.1\) eV, what will be the stopping potential for the photocurrent?
1. | \(1\) V | 2. | \(2.1\) V |
3. | \(3.1\) V | 4. | Zero |