If a light of amplitude A and wavelength λ is incident on a metallic surface, then the saturation current flow is proportional to (assume cut-off wavelength = ):
1.
2.
3.
4.
Light of wavelength \(3000 ~{\mathring{\mathrm{A}}}\) in Photoelectric effect gives electron of maximum kinetic energy \(0.5 ~\text{eV}\). If the wavelength changes to \(2000 ~{\mathring{\mathrm{A}}}\) then the maximum kinetic energy of emitted electrons will be:
1. | less than \(0.5 ~\text{eV}\) |
2. | \(0.5 ~\text{eV}\) |
3. | greater than \(0.5 ~\text{eV}\) |
4. | the photoelectric effect does not occur |
If the K.E. of an electron and a photon is the same, then the relation between their de-Broglie wavelength will be:
1.
2.
3.
4.
The total energy of an electron is \(3.555~\text{MeV}\). Its kinetic energy will be:
1. \(3.545~\text{MeV}\)
2. \(3.045~\text{MeV}\)
3. \(3.5~\text{MeV}\)
4. none of the above
The value of Planck's constant is:
1.
2.
3.
4.
If particles are moving with the same velocity, then the de-Broglie wavelength is maximum for:
1. proton
2. \(\alpha-\)particle
3. neutron
4. \(\beta-\)particle
When ultraviolet rays strike a metal plate, the photoelectric effect does not occur. It occurs by the incidence of:
1. Infrared rays
2. X-rays
3. Radio wave
4. Lightwave
Which of the following is not the property of cathode rays:
1. | it produces a heating effect. |
2. | it does not deflect in the electric field. |
3. | it casts a shadow. |
4. | it produces fluorescence. |
Which one among the following shows the particle nature of light?
1. Photoelectric effect
2. Interference
3. Refraction
4. Polarisation
A photo-cell is illuminated by a source of light, which is placed at a distance \(d\) from the cell. If the distance becomes \(\frac{d}{2}\), then the number of electrons emitted per second will be:
1. same
2. four times
3. two times
4. one-fourth