Advertisements
Advertisements
प्रश्न
The threshold wavelength of silver is 3800Å. Calculate the maximum kinetic energy in eV of photoelectrons emitted, when ultraviolet light of wavelength 2600Å falls on it.
(Planck’s constant, h =6.63 x 1O-34J.s.,
Velocity of light in air, c = 3 x 108 m / s)
उत्तर
Wavelength of silver, λ1 = 3800 Aº
Wavelength of ultraviolet light, λ2 = 2600 Aº
H = 6.63 × 10-34 Js
Velocity of light in air, c = 3 × 108 m/s
To calculate kinetic energy, K.E. = hv − hvº
`"K.E."="hc"[1/lambda-1/lambda_o]`
`"K.E."=19.89xx10^-19[1/2.6-1/3.8]`
`"K.E."=(2.416xx10^-19)/(1.6xx10^-19)`
K.E. = 1.51 eV
Hence, the maximum kinetic energy emitted by the photoelectron is 1.51 eV.
APPEARS IN
संबंधित प्रश्न
The photoelectric threshold wavelength of a metal is 230 nm. Determine the maximum kinetic energy in joule and in eV of the ejects electron for the metal surface when it is exposed to a radiation of wavelength 180 nm.
[Planck’s constant : h = 6.63 * 10-34 Js, Velocity of light : C = 3 * 108 m/s.]
Find the value of energy of electron in eV in the third Bohr orbit of hydrogen atom.
(Rydberg's constant (R) = 1· 097 x 107m - 1,Planck's constant (h) =6·63x10-34 J-s,Velocity of light in air (c) = 3 x 108m/ s.)
Find the wave number of a photon having energy of 2.072 eV
Given : Charge on electron = 1.6 x 10-19 C,
Velocity of light in air = 3 x 108 m/s,
Planck’s constant = 6.63 x 10-34 J-s.
State two important properties of photon which are used to write Einstein’s photoelectric equation.
Define (i) stopping potential and (ii) threshold frequency, using Einstein’s equation and drawing necessary plot between relevant quantities.
A proton and a deuteron are accelerated through the same accelerating potential. Which one of the two has less momentum?
Give reasons to justify your answer.
Radiation of frequency 1015 Hz is incident on two photosensitive surface P and Q. There is no photoemission from surface P. Photoemission occurs from surface Q but photoelectrons have zero kinetic energy. Explain these observations and find the value of work function for surface Q.
The work function for a metal surface is 2.2eV. If the light of wavelength 5000Å is incident on the surface of the metal, find the threshold frequency and incident frequency. Will there be an emission of photoelectrons or not? (c = 3 x 108 m/ s, 1eV = 1.6x10-19 J , h = 6.63 x 10-34 J.s.)
Write the basic features of photon picture of electromagnetic radiation on which Einstein’s photoelectric equation is based.
According to Einstein’s model, the threshold frequency for a metal having work function ϕ0 is given by _________.
Calculate the maximum kinetic energy of photoelectrons emitted by a metal (work function = 1.5 eV) when it is illuminated with light of wavelength 198 nm.
Plot a labelled graph of |Vs| where Vs is stopping potential versus frequency f of the incident radiation. State how will you use this graph to determine the value of Planck's constant?
A police van moving on a highway with a speed of 30 km/h fires a bullet at a thief's car speeding away in the same direction with a speed of 192 km/h. If the muzzle speed of the bullet is 150 m is, with what speed does the bullet hit the thief's car?
In an inelastic collision, which of the following does not remain conserved?
According to Einstein's photoelectric equation, the plot of the kinetic energy of the emitted photoelectrons from a metal Vs the frequency of the incident radiation gives as straight the whose slope:
Dimensions of ‘resistance’ are same as (where h is Planck's constant and e is charge):
Einstein work on the photoelectric effect provided support for the eqn:-
Who indirectly determined the mass of the electron by measuring the charge of the electrons?
The slope of frequency of incident light and stopping potential for a given surface will be
What will be wavelength of a photon of momentum 6.6 × 10–24 kgms–1?
What is the momentum of photon of energy 3 mev in kg ms-1?
The wavelength of matter is independent of
- Calculate the energy and momentum of a photon in a monochromatic beam of wavelength 331.5 nm.
- How fast should a hydrogen atom travel in order to have the same momentum as that of the photon in part (a)?
- Calculate the frequency of a photon of energy 6.5 × 10−19 J.
- Can this photon cause the emission of an electron from the surface of Cs of work function 2.14 eV? If yes, what will be the maximum kinetic energy of the photoelectron?
Ultraviolet light is incident on metals P, Q and R, having work functions 8 eV, 2 eV and 4 eV respectively,
- Which metal has lowest threshold frequency for photoelectric effect?
- For which metal is the value of Emax minimum?
(Note: Emax is maximum kinetic energy of the emitted photoelectrons.)
How does stopping potential in photoelectric emission vary if the intensity of the incident radiation increases?
