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# Solve! Ejection of the photoelectron from metalin the photoelectric effect experiment canbe stopped by applying 0.5 V when theradiation of 250 nm is used. The workfunction of the metal is :

Ejection of the photoelectron from metal in the photoelectric effect experiment can be stopped by applying 0.5 V when the radiation of 250 nm is used. The work function of the metal is :

• Option 1)

4 eV

• Option 2)

4.5 eV

• Option 3)

5 eV

• Option 4)

5.5 eV

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As we learned

Photoelectric Effect -

$\frac{1}{2}mu^{2}= hv-hv_{0}$

- wherein

where

m is the mass of the electron

u is the velocity associated with the ejected electron.

h is plank’s constant.

v is frequency of photon,

v0 is threshold frequency of metal.

$\lambda = 250 nm = 2500\AA$

$E =\frac{hc}{\lambda }=\frac{12400}{2500}=4.96eV$

$K\cdot E\cdot =$ ltopping potential = 0.5 eV

$E=W_{0}+K\cdot E\cdot$

$4.96=W_{0}+0.5$

$W_{0}= 4.46eV \approx 4.5eV$

Option 1)

4 eV

Option 2)

4.5 eV

Option 3)

5 eV

Option 4)

5.5 eV

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