Question

The work function for potassium and caesium is 2.25 ev and 2.14 ev respectively .is the photoeletctirc effect possible for either of them if the incident wevelnght is 5180°A​

Answer 1

Answer:

energy of wave with wavelength 5180 A° is

E = 12400 / 5180 = 2.39 eV

here both metals have work function less than 2.38 eV hence both will show photoelectric effect..

hope it helps..

plz mark BRAINLIEST

Answer 2

In both case photoelectric effect is possible .

Given :

Work function for potassium and caesium is 2.25 eV and 2.14 eV respectively.

Wavelength of given light , $\lambda=5180\ Angstrom=5.18\times 10^{-7}\ m\ .$

We know , photoelectric effect is only possible when incident energy of photons of given light is greater than the work function .

Therefore , Incident energy of photons , $E=\dfrac{hc}{\lambda}$

Putting value of $h=6.626\times 10^{-34} \ J.s$ and $c=3\times 10^8\ m/s$ .

We get ,

$\dfrac{6.626\times 10^{-34} \times 3\times 10^8}{5.18\times 10^{-7}}\\\\E=3.84\times 10^{-19}\ J.$

Converting it into eV by dividing with charge of electron.

We get ,

$E=\dfrac{3.84\times 10^{-19}}{1.6\times 10^{-19}}\\\\E=2.4\ eV$

Since , the energy is greater than the work function of both potassium and caesium .

Therefore , in both case photoelectric effect is possible .

Hence , this is the required solution .

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