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प्रश्न
The graph shows the variation of stopping potential with frequency of incident radiation for two photosensitive metals A and B. Which one of the two has higher value of work-function? Justify your answer.
The graph shows variation of stopping potential V0 versus frequency of incident radiation v for two photosensitive metals A and B. Which of the two metals has higher threshold frequency and why?
उत्तर
eV0=hν−hν0
`V_0-h/ev-h/ev_0`
Here, e is the charge of an electron, Vo is the stopping potential, h is Planck's constant, ν0 is the threshold frequency and ν is the frequency of the incident light.
On comparing with y=mx+c, we find that the more the magnitude of intercept on y or V0 axis, the more is the threshold frequency (ν0).
From the graph, the threshold frequency for metal A is greater than that for metal B. Hence, the work function for metal A is greater than that for metal B.
संबंधित प्रश्न
Sketch the graphs showing variation of stopping potential with frequency of incident radiations for two photosensitive materials A and B having threshold frequencies vA > vB.
(i) In which case is the stopping potential more and why?
(ii) Does the slope of the graph depend on the nature of the material used? Explain.
Light of intensity ‘I’ and frequency ‘v’ is incident on a photosensitive surface and causes photoelectric emission. What will be the effect on anode current when the anode potential is increased? In each case, all other factors remain the same. Explain, giving justification in each case.
The work functions for potassium and caesium are 2.25 eV and 2.14 eV respectively. Is the photoelectric effect possible for either of them if the incident wavelength is 5180 Å?
[Given : Planck’s constant = 6.63 x 10–34 J.s.;
Velocity of light = 3 x 108 m/s; 1 eV = 1.6 x 10–19 J]
What change will you observe if intensity of incident radiation is changed but the frequency remains the same?
A beam of monochromatic radiation is incident on a photosensitive surface. Answer the following question giving reason :
Does the kinetic energy of the emitted electrons depend on the intensity of incident radiation?
A beam of monochromatic radiation is incident on a photosensitive surface. Answer the following question giving reason :
On what factors does the number of emitted photoelectrons depend?
Calculate the momentum of a photon of energy 6 x I 0-19 J.
With reference to the photoelectric effect, what is meant by threshold wavelength?
Photoelectric effect is possible ______.
Consider an electron in front of metallic surface at a distance d (treated as an infinite plane surface). Assume the force of attraction by the plate is given as `1/4 q^2/(4πε_0d^2)`. Calculate work in taking the charge to an infinite distance from the plate. Taking d = 0.1 nm, find the work done in electron volts. [Such a force law is not valid for d < 0.1nm].
