A hypothetical particle has a mass of 510 MeV/c2. If such a ...

[meagbuch]

A hypothetical particle has a mass of 510 MeV/c2. If such a particle at rest decays into two gamma-ray photons, what is the wavelength of each photon?
 
  (1 eV = 1.60  10-19 J, c = 3.00  108 m/s, h = 6.626  10-34 J s)

Question 2

A nearsighted person has a far point that is 4.2 m from his eyes. What focal length lenses must he use in his contact lenses to allow him to focus on very distant mountains?
 
  A) -4.8 m B) -5.2 m C) 4.2 m D) -4.2 m E) 5.2 m

[bhavsar]

Answer to Question 1

4.87  10-15 m

Answer to Question 2

D

[meagbuch]

TY

[bhavsar]

You're welcome