If the binding energy of electrons in a metal | vedclass

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Question

(A) The binding energy (work function) for $1 \ mol$ of electrons is $250 \ kJ \ mol^{-1}$.To find the energy for a single electron,divide by Avogadro

Vedclass · Accepted Answer

$6.26 	imes 10^{14} \ s^{-1}$

Vedclass · Answer

(A) The binding energy (work function) for $1 \ mol$ of electrons is $250 \ kJ \ mol^{-1}$.To find the energy for a single electron,divide by Avogadro's number $(N_A = 6.022 	imes 10^{23} \ mol^{-1})$:$E = \frac{250 	imes 10^3 \ J \ mol^{-1}}{6.022 	imes 10^{23} \ mol^{-1}} = 4.151 	imes 10^{-19} \ J$.The threshold energy is given by $E = h 
u_0$,where $h = 6.626 	imes 10^{-34} \ J \ s$.$
u_0 = \frac{E}{h} = \frac{4.151 	imes 10^{-19} \ J}{6.626 	imes 10^{-34} \ J \ s} \approx 6.26 	imes 10^{14} \ s^{-1}$.Thus,the correct option is $A$.

If the binding energy of electrons in a metal is $250 \ kJ \ mol^{-1}$,what should be the threshold frequency of the striking photons in order to free an electron from the metal surface?

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