Photoelectric EffectHard
Question
In a photoelectric experiment, with light of wavelength λ, the fastest electron has speed v. If the exciting wavelength is changed to 
, the speed of the fastest emitted electron will become
, the speed of the fastest emitted electron will becomeOptions
A.v
B.v
C.less than v
D.greater than v
Solution
In photoelectric experiment, speed of fastest emitted electron is given by -
mv2max = 
− w
Case - I :
mv2 = − w ...........(i)
Case - II :
mv′2 = 
mv′2 = 
...........(ii)
From eqn. (i) & (ii)
v′2 =
Hence, v′ > v
.
mv2max = − wCase - I :
mv2 = − w ...........(i)Case - II :
mv′2 = mv′2 = ...........(ii)From eqn. (i) & (ii)
v′2 =
Hence, v′ > v
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