In a photocell bi chromatic light of wave length `2480 A^(0) ` and `6000 Aoverset(0)` are incident on a cathode whose workfunction is `4.8eV`.If a uniform magnetic field of `3xx10^(-5) T` exists parallel to the plate, find the radius of the circular path described by the photoelectron. (mass of electron is `9xx10^(-31)kg`)

In a photocell bi chromatic light of wave length `2480 A^(0) ` and `60

1.	In a photocell bi chromatic light of wave length `2480 A^(0) ` and `6000 Aoverset(0)` are incident on a cathode whose workfunction is `4.8eV`.If a uniform magnetic field of `3xx10^(-5) T` exists parallel to the plate, find the radius of the circular path described by the photoelectron. (mass of electron is `9xx10^(-31)kg`)
Answer» `E_(1)=12400/lambda_(1)=12400/2480=5eV, E_(2)=12400/lambda_(2)=12400/6000=2.06eV,` As `E_(2) lt W_(0)` and `E_(1) lt W_(0)`, photo electric emission is possible only with `lambda_(1)`. Maximum `K.E` of emitted photo electrons `K=E_(1) - W_(0)=0.2eV` Photo electrons experience magnetic force and move along a circular path of radius `r=(mnu)/(Bq)=sqrt(2mK)/(Bq) rArr=5cm`.

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