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Asked by jain.pradeep | 17th Feb, 2020, 08:11: PM

Expert Answer:

Equation of Photoelectric effect is given as,
 
KEmax = E - φ  ...................(1)
 
where KEmax is maximum kinetic energy of electron ejected out due to photoelectric effect,
E is energy of incident photon and φ is the workfunction.
 
if the incident light is of wavelength λ = 2500 Ao , then incident light energy E = ( h c )/λ
 
E = [ 6.626 × 10-34 × 3 × 108 ] / ( 2500 × 10-10 ) = 7.95 × 10-19 J
 
Hence maximum kinetic energy obtained from eqn.(1) as,
 
KEmax = 7.95 × 10-19 - ( 3.5 × 1.602 ×  10-19 ) = 2.343 × 10-19  J
 
Minimum kinetic energy will be very near to 0
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when same light falls on a surface of other material that has work function 5.5 eV , i.e 5.5 × 1.602 × 10-19 J or 8.811 × 10-19 J ,
there will not be any phot electron ejected out because incident energy 7.95 × 10-19 J is less than workfunction

Answered by Thiyagarajan K | 17th Feb, 2020, 09:19: PM

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