What is the minimum energy which a gamma ray photon must possess in order to produce electron positron pair ?

Explanation

To determine the minimum energy that a gamma ray photon must possess in order to produce an electron-positron pair, we can follow these steps:

### Step 1: Understand the Mass of the Particles
The electron and positron have the same mass. The mass of an electron (or positron) is given as:
\[ m_e = 9.1 \times 10^{-31} \, \text{kg} \]

### Step 2: Calculate the Total Mass for the Pair
Since an electron and a positron are produced, the total mass (Δm) involved in the pair production is:
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