Question

using radiation of wavelength 3500A° it is observed that the maximum kinetic energy of the emitted photoelectrons is 1.6ev for potassium , calculate the work function of the metal . ( h= 6.626× 10'-34js , 1ev = 1.6 × 10'-19 j.​

Answer 1

Given :-

• Wavelength of radiation , λ = 3500A°
• The maximum K.E = 1.6 ev
• h = 6.626 × 10' - 34js
• 1ev = 1.6.× 10'-19js
• Speed of light = c = 3x10' 8 m/s

To find ?

• Work function of the metal ?

Calculation :-

- Work function of metal is the minimum energy required to extract one electron from the surface of a given solid or metal

φm = Evac(s) - EF

- Since work function does not depend on wavelength of incident light so it will be constant because the energy of the photon must be greater than the work function in photoelectric effect.

• W = hc / λ2 −eV S1
• λ=hc/W
• W = hc × λ
• W = [6.626 × 10' - 34] [3x10' 8] × [3500]
• W = [6.626 × 10' - 34] [3x10' 8] × [3500]W
• W = 19.86 × 10' -27

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Answer 2

Answer:

2ev

Explanation: