Question 142 of 200
With reference to the observations in photo-electric effect, identify the correct statements from below:
A. The square of maximum velocity of photoelectrons varies linearly with frequency of incident light.
B. The value of saturation current increases on moving the source of light away from the metal surface.
C. The maximum kinetic energy of photo-electrons decreases on decreasing the power of LED (light emitting diode) source of light.
D. The immediate emission of photo-electrons out of metal surface can not be explained by particle nature of light/electromagnetic waves.
E. Existence of threshold wavelength can not be explained by wave nature of light/electromagnetic waves.
Choose the correct answer from the options given below:
Show answer and solution
Answer: (B) A and E only
From Einstein's photoelectric equation,
Maximum kinetic energy, , where, is maximum velocity of photoelectrons, is Planck's constant, is frequency of incident light and is work function of metal.
From above relation, we can see that the square of maximum velocity of photoelectrons varies linearly with frequency of incident light.
If we increase the intensity of the incident radiation by keeping the frequency constant, then the value of saturation current increases in proportion to the intensity of the incident radiation. Thus, saturation current decreases on moving the source of light away from the metal surface.The kinetic energy of the photoelectrons is directly proportional to the light frequency, and it remains constant as light amplitude or power of source increases.
Photoelectric effect cannot be explained on the basis of wave nature because experimentally a particular energy called the work function of the metal surface in needed to eject electrons from surface, irrespective of the time for which light is incident.
Photoelectric effect can be explained by particle nature of light (i.e. quantum theory). Threshold wavelength is maximum wavelength at which emission takes place.
Maximum kinetic energy, , where, is maximum velocity of photoelectrons, is Planck's constant, is frequency of incident light and is work function of metal.
From above relation, we can see that the square of maximum velocity of photoelectrons varies linearly with frequency of incident light.
If we increase the intensity of the incident radiation by keeping the frequency constant, then the value of saturation current increases in proportion to the intensity of the incident radiation. Thus, saturation current decreases on moving the source of light away from the metal surface.The kinetic energy of the photoelectrons is directly proportional to the light frequency, and it remains constant as light amplitude or power of source increases.
Photoelectric effect cannot be explained on the basis of wave nature because experimentally a particular energy called the work function of the metal surface in needed to eject electrons from surface, irrespective of the time for which light is incident.
Photoelectric effect can be explained by particle nature of light (i.e. quantum theory). Threshold wavelength is maximum wavelength at which emission takes place.