Question

In the presence of a nucleus the energy of a y-ray photon can be converted into an electron-positron pair. Calculate the minimum energy for this to occur and thus the frequency of such a photon. Hint: use E = mc2.]

Answer 1

Answer:

Explanation:

mass of electron in amu = .000549

mass of electron = mass of proton

total mass of electron and proton = 2 x1.098 x 10⁻³ = 2.196 x 10⁻³ amu

1 amu = 931 x 10⁶ eV

2.196 X 10⁻³ amu = 2.196 x 931 x 10³ eV

= 2.044 X 10⁶ eV.

= 2044 X 10³ ev

So minimum energy required = 2044 x 10³ eV.

Wavelength of photon required = 12375/2044 x 10³ A

= 6.054 X 10⁻³A. =6.054 X 10⁻¹³ m

frequency of photon  = 3 x 10⁸/6.054x 10⁻¹³

= .4955 x 10¹⁶Hz.

= 4.955 x 10¹⁵ Hz