Question

The work function (Q) of some metals is listed below. The number of metals which will show
photo electric effect when light of 300 nm wavelength falls on the metal is : (IIT 2011)
Na
Mg Cu Ag Fe PE
Qren
2.2 3-7 4-8 4.3
6-3 4.75
[Ans. Li, Na, K, Mgl
5. Calculate the wavelength of radiation emitted by LiP- electron in jumping from second orbit to
first orbit.
(Ans. 13-5 nm)
1
1
= 1-09677
10 22
m-]
772
please solve​

Answer 1

Answer:

Energy of photon,

E=

λ

hc

J=

eλ

hc

eV=

300×10

−9

×1.602×10

−19

6.625×10

−34

×3×10

8

=4.14eV

For the photoelectric effect, ϕ<E=4.14

Here, only Li, Na, K, and Mg have work functions less than 4.14 V.

So, only these metals will show the photoelectric effect with this photon.