English

Explain the inverse linear dependence of stopping potential on the incident wavelength in a photoelectric effect experiment.

Advertisements
Advertisements

Question

Explain the inverse linear dependence of stopping potential on the incident wavelength in a photoelectric effect experiment.

Answer in Brief
Advertisements

Solution

When a beam of light of a specific wavelength (or frequency) strikes the metal's surface, the total number of electrons ejected and the kinetic energy of each electron is given by,
K.Emax ​= `"hc"/lambda - phi,`
Where, V0​ is stopping potential.
So, `"V"_0"e" = "hc"/lambda - phi,`
where V0 is the stopping potential, e is the charge magnitude on the electron, h is Planck's constant, c is the speed of light in free space, λ is the wavelength of the electromagnetic radiation incident on a metal surface and Φ is the work function for the metal, h, c and e are constants. For a specific metal, Φ is constant.

Hence, it follows that as `1/lambda` increases, V0 increases.
The plot of V0 verses `1/lambda` is linear. This is due to the fact that the energy associated with a quantum of radiation (photon) is directly proportional to its frequency and thus inversely proportional to its wavelength of radiation.

shaalaa.com
  Is there an error in this question or solution?
Chapter 14: Dual Nature of Radiation and Matter - Exercises [Page 322]

APPEARS IN

Balbharati Physics [English] Standard 12 Maharashtra State Board
Chapter 14 Dual Nature of Radiation and Matter
Exercises | Q 3 | Page 322

RELATED QUESTIONS

If the frequency of incident light falling on a photosensitive material is doubled, then the kinetic energy of the emitted photoelectron will be ______.


The maximum kinetic energy of the photoelectrons depends only on ______ 


Planck's constant is 6.6 × 10-34 Js. The momentum of each photon is given radiation Is 3.3 × 10-29 kg/s. The λ of radiation is ______.


Explain the concept of the photoelectric effect. 


If the total energy of radiation of frequency 1014 Hz is 6.63 J, Calculate the number of photons in the radiation. 


The energy of the incident photon on the metal surface is 3 W and then 5 W, where W is the work function for that metal. The ratio of velocities of emitted photoelectrons is ______.


The kinetic energy of the most energetic photoelectron emitted from a metal surface is doubled when the wavelength of the incident radiation is reduced from λ1 to λ2. The work function of the metal is ______


Which one of the following is TRUE in photoelectric emission?


When light falls on a metal surface, the maximum kinetic energy of the emitted photoelectrons depends upon ______


The maximum velocity of the photoelectron emitted by the metal surface is 'v '. Charge and mass of the photoelectron is denoted by 'e' and 'm' respectively. The stopping potential in volt is ______.


The maximum velocity of the photoelectron emitted by the metal surface is 'v '. Charge and mass of the photoelectron is denoted by 'e' and 'm' respectively. The stopping potential in volt is ______.


For photoelectric emission from certain metal, the cut-off frequency is v. If radiation of frequency 2v impinges on the metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass) ____________.


When a light of wavelength 4000 Å falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, light of wavelength 6000 Å is sufficient for photo emission. The work functions of the two emitters are in the ratio of ____________.


Light of wavelength `lambda` strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is to be increased to 2E, the wavelength must be changed to `lambda'` where ____________.


Threshold wavelength for lithium metal is 6250 Å. For photoemission, the wavelength of the incident light must be ______.


In photoelectric effect, for a light of different intensities but of same frequency, the stopping potential for a given metal is ____________.


In photoelectric effect, graph of saturation current versus frequency of light is plotted. The nature of the graph will be ____________.


The photo electric effect to take place for a metal, the minimum frequency required is 5.792 × 1014 Hz. A light of wavelength 6000 Å is incident on that metal surface. What is the corresponding frequency of light and will there be photoelectric emissions? [velocity of light = 3 × 108 m/s]


Light of different frequencies, whose photons have energies 3 eV and 18 eV respectively, successively illuminate a metal of work function 2 eV. The ratio of the maximum speeds of the emitted electrons will be ______.


The work function of a substance is 4.0 eV. The longest wavelength of light that can cause photo-emission from this substance is approximately (h = 6.63 × 10-34 Js)[1eV = 1.6 × 10-19 J]


The photon of frequency vis incident on a metal surface whose threshold frequency is v0. The kinetic energy of the emitted photoelectrons will be ______.


When a certain metallic surface is illuminated with monochromatic light of wavelength '`lambda`', the stopping potential for photoelectric effect is '3V0'. If the same surface is illuminated with a light of wavelength '`2 lambda`', the stopping potential is found as 'V0'. The threshold wavelength for this surface is ____________.


When radiation of wavelength λ is used to illuminate a metallic surface, the stopping potential is V. When the same surface is illuminated with radiation of wavelength 3λ, the stopping potential is `"V"/4`. If the threshold wavelength for the metallic surface is nλ. then value of n will be ______.


The maximum kinetic energy of the photoelectrons ejected will be ______ eV when the light of wavelength 350 nm is incident on a cesium surface. The work function of cesium = 1.9 eV.


A point isotropic light source of power P = 12 watts is located on the axis of a circular mirror of radius R = 3 cm. If the distance of the source from the centre of the mirror is a = 39 cm and the reflection coefficient of the mirror is α = 0.70 then the force exerted by the light ray on the mirror is ______ × 10-10 N.


A charged dust particle of radius 5 × 10-7 m is located in a horizontal electric field having an intensity of 6.28 × 105 V/m. The surrounding medium is air with a coefficient of viscosity η = 1.6 × 10-5 N-s/m2. If the particle moves with a uniform horizontal speed of 0.02 m/s, the number of electrons on it is ______.


Photoelectric emission is observed from a metallic surface for frequencies ν1 and ν2 of the incident light rays (ν1 > ν2). If the ratio of the maximum value of the kinetic energy of the photoelectrons emitted in the first case to that in the second case is 2 : K, then the threshold frequency of the metallic surface is ______.


Define photoelectric work function of a metal.


In a photoelectric experiment, the stopping potential is 1.5V. What is the maximum kinetic energy of a photoelectron?


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×