Question

Identify the correct statement/s from the following A. Total mass of positron and electron is equivalent to 1.02 MeV
B. Nucleus or material is not needed for pair annihilation.
C. For pair production maximum photon wavelength is 1.2 pm.
D. Pair production can occur in empty space.
E. Nucleus or material is not needed for pair production. Choose the correct answer from the options given below:

• A. A, B, C only
• B. B, C, D only
• C. C, D, E only
• D. D, E, A only

Hint:

Pair production requires nearby nucleus for momentum conservation.

Answer 1

The Correct Option is A

Concept:
Pair production and annihilation involve conversion between matter and energy.
Step 1:
Electron and positron each have rest mass energy: \[ 0.51~MeV \] Total: \[ 1.02~MeV \] Thus A is correct.
Step 2:
Pair annihilation can occur without nucleus. Thus B is correct.
Step 3:
For pair production threshold wavelength: \[ \lambda \approx 1.2~pm \] Thus C is correct. Pair production cannot occur in empty space and requires nucleus. Thus D and E are incorrect.
Step 4:
Correct statements are: \[ A,\quad B,\quad C \] \[ \boxed{\text{Correct Option = (1)}} \]