Question

The maximum wavelength that an electromagnetic wave can

haveand still eject electrons from a metal surface is 440 nm. What
is the work functionW0 of this metal? Express
your answer inelectrons volts.

Answer 1

Work function will be 2.8125 eV

Step-by-step explanation:

We have given maximum wavelength that electromagnetic wave emit
`\lambda =440nm=440* 10^(-9)m`

Plank's constant
`h=6.6* 10^(-34)Js`

Speed of light
`c=3* 10^8m/sec`

Work function is equal to
`W=(hc)/(\lambda )=(6.6* 10^(-34)* 3* 10^8)/(440* 10^(-9))=4.5* 10^(-19)j`

We know that
`1ev=1.6* 10^(-19)j`

So
`4.5* 10^(-19)j=2.8125eV`