## 1.B.16

$\lambda=\frac{h}{p}$

ShravanPatel2B
Posts: 100
Joined: Fri Aug 30, 2019 12:18 am

### 1.B.16

The work function for chromium metal is 4.37 eV. What wavelength of radiation must be used to eject electrons with a velocity of 1.5 x 10^3 km*s^-1?

Has anyone solved this problem, and if so what steps did you take to get to your answer?
I used the formula kinetic energy = energy of photon - work function and solved for the energy of the photon. I then used E = hc(lambda)^-1 to solve for the wavelength. I got 1.15 x 10^-7 m as my answer. Did anyone else get this?

Thanks!

Ariana Iranmahboub1G
Posts: 114
Joined: Fri Aug 09, 2019 12:17 am

### Re: 1.B.16

I converted 4.37 eV to joule and 1.5 x 10^3 km*s^-1 to m*s^-1. Then, I also used the formula, kinetic energy = energy of photon - work function, to solve for the energy of the photon. After, I used E = (h*c)/lambda to solve for the wavelength, which gave me the answer 1.52 X 10^-7 m, or 115nm.

Dan M -3E
Posts: 101
Joined: Wed Sep 18, 2019 12:19 am

### Re: 1.B.16

Yup did the same thing and got the same answer as you guys.