physics questions

Question

1. How fast must an electron move if it is to have a de Broglie wavelength of 3.9 ✕ 10-11 m?

 

2.What is the speed of a proton with a de Broglie wavelength of 3.20 ✕ 10-14 m?

Answer 1

(1)

 

λ = h/(mv) ⇒

 

v = h/(mλ)

 

Plug in λ (given), h (Planck's constant), and the mass of an electron.

 

(2)

 

Same equation as in part (1), but plug in the given λ and the mass of a proton.