Photoelectric Effect and WaveParticle Duality Physics - Photoelectric Effect and WaveParticle Duality

A point source of light is used in a photoelectric effect. If the source is removed farther from the emitting metal, the stopping potential:

1. Will increase.
2. Will decrease.
3. Will remain constant.
4. Will either increase or decrease.

The equation E = pc is valid:

1. For an electron as well as for a photon.
2. For an electron but not for a photon.
3. For a photon but not for an electron.
4. Neither for an electron nor for a photon.

Photoelectric effect supports quantum nature of light because:

1. There is a minimum frequency below which no photoelectrons are emitted.
2. The maximum kinetic energy of photoelectrons depends only on the frequency of light and not on its intensity.
3. Even when the metal surface is faintly illuminated the photoelectrons leave the surface immediately.
4. Electric charge of the photoelectrons is quantized.

In an experiment on photoelectric effect, a photon is incident on an electron from one direction and the photoelectron is emitted almost in the opposite direction. Does this violate conservation of momentu?

Consider the situation described in the previous problem. Show that the force on the sphere due to the light falling on it is the same even if the sphere is not perfectly absorbing.

A sphere of radius 1.00cm is placed in the path of a parallel beam of light of large aperture. The intensity of the light is 0.5W/cm^-2. If the sphere completely absorbs the radiation falling on it, find the force exerted by the light beam on the sphere.

Can a photon be deflected by an electric field? By a magnetic field?

Calculate the momentum of a photon of light of wavelength 500nm.

An atom absorbs a photon of wavelength 500nm and emits another photon of wavelength 700nm. Find the net energy absorbed by the atom in the process.

If an electron has a wavelength, does it also have a colour?

A parallel beam of monochromatic light of wavelength 663nm is incident on a totally reflecting plane mirror. The angle of incidence is 60° and the number of photons striking the mirror per second is 1.0 × 10¹⁹. Calculate the force exerted by the light beam on the mirror.

A photographic film is coated with a silver bromide layer. When light fells on this film, silver bromide molecules dissociate end the film records the light there. A minimum of 0.6eV is needed to dissociate a silver bromide molecule. Find the maximum wavelength of light that can be recorded by the film.

Can we find the mass of a photon by the definition p = mv?

ls it always true that for two sources of equal intensity, the number of photons emitted in a given time are equal?

A totally reflecting, small plane mirror placed horizontally faces a parallel beam of light, as shown in the figure. The mass of the mirror is 20g. Assume that there is no absorption in the lens and that 30% of the light emitted by the source goes through the lens. Find the power of the source needed to support the weight of the mirror. Take g = 10m/s².

Should the energy of a photon be called its kinetic energy or its internal energy?

A hot body is placed in a closed room maintained at a lower temperature. Is the number of photons in the room increasing?

A silver ball of radius 4.8cm is suspended by a thread in a vacuum chamber. Ultraviolet light of wavelength 200 run is incident on the ball for some time during which a total light energy of 1.0 × 10^-7J falls on the surface. Assuming that on the average one photon out of every ten thousand is able to eject a photoelectron, find the electric potential et the surface of the bell assuming zero potential at infinity. What is the potential at the centre of the bell?

A beam of white light is incident normally on a plane surface absorbing 70% of the light and reflecting the rest. If the incident beam carries 10W of power, find the force exerted by it on the surface.

It is found that yellow light does not eject photoelectrons from a metal. Is it advisable to try with orange light? With green light?

Find the maximum magnitude of the linear momentum of a photoelectron emitted when light of wavelength 400 run falls on a metal having work function 2.5eV.