Advertisements
Advertisements
प्रश्न
The work function for a certain metal is 4.2 eV. Will this metal give photoelectric emission for incident radiation of wavelength 330 nm?
Advertisements
उत्तर
Work function of the metal, `phi_0` = 4.2 eV
Charge on an electron, e = 1.6 × 10−19 C
Planck’s constant, h = 6.626 × 10−34 Js
Wavelength of the incident radiation, λ = 330 nm = 330 × 10−9 m
Speed of light, c = 3 × 108 m/s
The energy of the incident photon is given as:
E = `(hc)/lambda`
= `(6.626 xx 10^(-34) xx 3 xx 10^8)/(330 xx 10^(-9))`
= 6.0 × 10−19 J
`= (6.0 xx 10^(-19))/(1.6 xx 10^(-19))`
= 3.76 eV
It can be observed that the energy of the incident radiation is less than the work function of the metal. Hence, no photoelectric emission will take place.
संबंधित प्रश्न
In an experiment on the photoelectric effect, the slope of the cut-off voltage versus the frequency of incident light is found to be 4.12 × 10−15 Vs. Calculate the value of Planck’s constant.
Write Einstein’s photoelectric equation?
Briefly explain the three observed features which can be explained by Einstein’s photoelectric equation.
Is p − E/c valid for electrons?
The frequency and intensity of a light source are doubled. Consider the following statements.
(A) The saturation photocurrent remains almost the same.
(B) The maximum kinetic energy of the photoelectrons is doubled.
Use Einstein’s photoelectric equation to show how from this graph,
(i) Threshold frequency, and (ii) Planck’s constant can be determined.
How does one explain the emission of electrons from a photosensitive surface with the help of Einstein’s photoelectric equation?
Choose the correct answer from given options
Photons of frequency v are incident on the surface of two metals A and B of threshold frequency 3/4 v and 2/3 v, respectively. The ratio of maximum kinetic energy of electrons emitted from A to that from B is
Radiation of frequency 1015 Hz is incident on three photosensitive surfaces A, B and C. Following observations are recorded:
Surface A: no photoemission occurs
Surface B: photoemission occurs but the photoelectrons have zero kinetic energy.
Surface C: photo emission occurs and photoelectrons have some kinetic energy.
Using Einstein’s photo-electric equation, explain the three observations.
If c is the velocity of light in free space, the correct statements about photon among the following are:
- The energy of a photon is E = hv.
- The velocity of a photon is c.
- The momentum of a photon, ρ = `(h v)/c`.
- In a photon-electron collision, both total energy and total momentum are conserved.
- Photon possesses positive charge.
Choose the correct answer from the options given below:
Which feature of photoelectric emission could classical wave theory not explain?
Einstein proposed that light energy is absorbed in discrete packets called what?
In \[E=h\nu\], what does \[\nu\] represent?
Which is Einstein’s photoelectric equation?
Which expression gives the maximum kinetic energy of emitted photoelectrons?
What does \[\phi_0\] represent in Einstein’s photoelectric equation?
Which expression gives the threshold frequency?
How can maximum kinetic energy be written in terms of stopping potential \[V_0\]?
Why does the maximum kinetic energy of photoelectrons increase when frequency increases?
