A photon of wavelenght is ` 4.0 xx 10^(-7) m` strikes on a mnetal surfce , the work function of metal being ` 3. 4xx 10^(-19) J`. Select the correct statyements :A. The enrgy of pghoton is ` 4. 97 x 10 ^(19) J`B. The kinetic enrgy fo the emeission is ` 1. 57 xx 10^(-19) J`C. The kinetic enrgy fo the emission is ` 0.98 eV`D. The velocity fo photoelectron is ` 5. 87 xx 10^5 ms^(-1)`.

A photon of wavelenght is ` 4.0 xx 10^(-7) m` strikes on a mnetal surf

1.	A photon of wavelenght is ` 4.0 xx 10^(-7) m` strikes on a mnetal surfce , the work function of metal being ` 3. 4xx 10^(-19) J`. Select the correct statyements :A. The enrgy of pghoton is ` 4. 97 x 10 ^(19) J`B. The kinetic enrgy fo the emeission is ` 1. 57 xx 10^(-19) J`C. The kinetic enrgy fo the emission is ` 0.98 eV`D. The velocity fo photoelectron is ` 5. 87 xx 10^5 ms^(-1)`.
Answer» Correct Answer - A::B::C::D `E//"photon" = ( h. c)/(lambda) = ( 6.625 xx 10^(-34) xx 3.0 xx 10^8)/( 4 .0 xx 10^(-7))` ` = 4.97 xx 10^(-19) J` K.E, of the emission `= E _("photon") - W` ` ( :. W= "work function of metal" )` ` =4. 97 xx 10^(-19) - 3 . 4 xx 10^(-19)` ` = 1. 57 xx 10^(-19) J = 0. 98 eV ( :. 1 eV = 1 . 602 xx 10^(-19) J)` ` :. K.E`. of meitted photoelectron `= 1/2` `mu^2` ` :. u = sqrt (( 2 xx k.E.)/(m))` ` = sqrt(( 2 xx 1. 57 xx 10^(-19))/(9. 1 xx 10^(31))` ` u = 5. 87 xx 10^5 ms^(-1)`.

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