InterviewSolution
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InterviewSolution
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Light of wavelength `2475 Å` is incident on barium. Photoelectrons emitted describe a circle of radius `100 cm` by a magnetic field of flux density `(1)/(sqrt(17)) xx 10^(-5) Tesla`. Work function of the barium is (Given `(e )/(m) = 1.7 xx 10^(11)`) |
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Answer» Radius of circular path described by a charged particle in a magnetic field is given by `r=sqrt((2mk)/(qB)) , rArr k=(q^2B^2 r^2)/"2m"=(e/m)(eB^2r^2)/2` `=1/2xx1.7xx10^11 xx 1.6 xx 10^(-19)xx(1/sqrt17 xx 10^(-5))^2xx(1)^2` `=8xx10^(-20) J ` =0.5 eV `E=phi+K_"max"` `phi=E-K_"max"` `=(-12375/2475)` eV-0.5 eV=4.5 eV |
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