Question

What is the maximum kinetic energy of ejected electrons when photons of wavelength 300 nm hit a metal that has a work function of 1.13 ev? A. 0.50 ev B. 1.0 ev C. 2.0 ev D. 3.0 eV E. 4.0 ev

Answer 1

Step-by-step explanation:

Given that,

Wavelength of the photon,
`\lambda=300\ nm=3* 10^(-7)\ m`

Work function of the metal,
`\phi=1.13\ eV=1.81* 10^(-19)\ J`

We need to find the maximum kinetic energy of the ejected electrons. It can be calculated using Einstein's photoelectric equation as :

`hf=E_k+\phi`

`E_k=hf-\phi`

`E_k=h(c)/(\lambda)-\phi`

`E_k=6.63* 10^(-34)* (3* 10^8)/(3* 10^(-7))-1.81* 10^(-19)`

`E_k=4.82* 10^(-19)\ J`

`E_k=3.01\ eV`

or

`E_k=3\ eV`

So, the maximum kinetic energy of the ejected electrons is 3 ev. Hence, this is the required solution.