Question

For pair production i.e. for the production of electron and positron incident photon must have minimum frequency of the order of –

• A. 10¹⁸/sec
• B. 10²¹/sec
• C. 10²⁵/sec
• D. 10³⁰/sec

Answer 1

Answer: (B)

10²¹/sec

Answer 2

Minimum energy involved in pair production is 1.02 MeV hν = 1.02 MeV

ν = $\frac { 1.02 \times 10 ^ { 6 } \times 1.6 \times 10 ^ { - 19 } } { 6.62 \times 10 ^ { - 34 } }$

ν ≈ 10⁴⁰ × 10^–19

ν ≈ 10²¹/sec