हिंदी

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

Advertisements
Advertisements

प्रश्न

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

संक्षेप में उत्तर
Advertisements

उत्तर

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
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 14: Dual Nature of Radiation and Matter - Exercises [पृष्ठ ३२२]

APPEARS IN

बालभारती Physics [English] Standard 12 Maharashtra State Board
अध्याय 14 Dual Nature of Radiation and Matter
Exercises | Q 3. | पृष्ठ ३२२

संबंधित प्रश्न

Is it always possible to see the photoelectric effect with a red light?


Observations from an experiment on the photoelectric effect for the stopping potential by varying the incident frequency were plotted. The slope of the linear curve was found to be approximately 4.1 × 10−15 V s. Given that Exercises the charge of an electron is 1.6 × 10−19 C, find the value of the Planck’s constant h.

Radiation of wavelength 4500 Å is incident on a metal having work function 2.0 eV. Due to the presence of a magnetic field B, the most energetic photoelectrons emitted in a direction perpendicular to the field move along a circular path of radius 20 cm. What is the value of the magnetic field B?


Draw a neat labelled diagram of a schematic of the experimental setup for the photoelectric effect. 


The work function of a surface is 3.1 eV. A photon of frequency 1 × 1015 Hz. Is an incident on it. Calculate the incident wavelength is photoelectric emission occurs or not.   


With the help of a circuit diagram describe the experiment to study the characteristics of the photoelectric effect. Hence discuss any 2 characteristics of the photoelectric effect.  


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) ____________.


A metal surface is illuminated by light of given intensity and frequency to cause photoemission. If the intensity of illumination is reduced to one-fourth of its original value then the maximum KE of the emitted photoelectrons would be ______.


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 ____________.


A metal surface is illuminated by photons of energy 5 eV and 2.5 eV respectively. The ratio of their wavelengths is ____________.


When certain metal surface is illuminated with a light of wavelength A., the stopping potential is V, When the same surface is illuminated by light of wavelength 2λ, the stopping potential is `("V"/3)`. The threshold wavelength for the surface is ______.


When wavelength of incident radiation on the metal surface is reduced from 'λ1' to 'λ2', the kinetic energy of emitted photoelectrons is tripled. The work function of the metal is ______.
(h = Planck's constant, c =velocity of light)


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


A light of wavelength '`lambda`' and intensity 'I' falls on photosensitive material. If 'N' photoelectrons are emitted, each with kinetic energy E, then ____________.


The ratio of slopes m1: ro2 of the lines given in the following graphs is, ______.


The radiation emitted, when an electron jumps from n = 3 to n = 2 orbit is a hydrogen atom, falls on a metal to produce photoelectron. The electrons from the metal surface with maximum kinetic energy are made to move perpendicular to a magnetic field of `1/320`T in a radius of 10-3m. Find the 320 work function of metal:


We wish to observe an object which is 2.5Å in size. The minimum energy photon that can be used ______.


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 ______.


Light of wavelength λ, which is less than threshold wavelength is incident on a photosensitive material. If incident wavelength is decreased so that emitted photoelectrons are moving with same velocity, then stopping potential will ______.


Light of two different frequencies whose photons have energies 1.3 eV and 2.8 eV respectively, successfully illuminate a metallic surface whose work function is 0.8 eV. The ratio of maximum speeds of emitted electrons will be ______.


The photoelectric threshold for a certain metal surface is 3600 Å. If the metal surface is irradiated by a wavelength of 1100 Å, then kinetic energy of the emitted photoelectrons is ______.


When monochromatic light of frequency v1 falls on a metal surface, the stopping potential required is found to be V1. If the radiation of frequency v2 is incident on the surface, the stopping potential required V2 is ______. (v2 > v1)


Explain the failure of wave theory of light to account for the observations from experiments on photoelectric effect.


The threshold frequency for a certain metal for photoelectric effect is 1.7 x 1015 Hz. When a light of frequency 2.2 x 1015 Hz is incident on the metal surface, the kinetic energy of the emitted photoelectrons is 3.3 x.10-19 J. Calculate Planck's constant.


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


A parallel plate capacitor with air between the plates has capacitance 9 pF. The separation between the plates becomes thrice and the space between them is filled with a medium of dielectric constant 6. The capacitance becomes 'x' pF. The value of 'x' is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×