## 1.33

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

Lina Petrossian 1D
Posts: 77
Joined: Fri Oct 05, 2018 12:16 am

### 1.33

The velocity of an electron that is emitted from a metallic surface by a photon is 3.6x10^3 km.s-1.
(a) What is the wavelength of the ejected electron?
(b) No electrons are emitted from the surface of the metal until the frequency of the radiation reaches 2.50x10^16 Hz. How much energy
is required to remove the electron from the metal surface?
(c) What is the wavelength of the radiation that caused photoejection of the electron?
(d) What kind of electromagnetic radiation was used?

Can someone explain how you solved each part of the problem and what answers you got?

Tamera Scott 1G
Posts: 65
Joined: Fri Sep 28, 2018 12:27 am

### Re: 1.33

I have yet to solve this problem, but I do know that for part a, you will need to use the DeBroglie equation of wavelength= h/mv. First, you will need to convert units before inputting anything into the equation. The velocity has to change from km*s^-1 to m*s^-1, so multiply (3.6 *10^3 km*s^-1) by (1000 m*km^-1), and the mass of an electron (9.911* 10^-28 g) has to be multiplied by (1kg/1000g) to get an answer in kg. For part b, I know that you need to use the equation E=hv, and for part c, you will need to use the kinetic energy formula, 1/2mv^2, and add this to the answer from part b. For part d, you just base the type of electromagnetic radiation from part c.