`C_(v)` values of He is always `(3R)/(2)` but `C_(v)` values of `H_(2)` is `(3R)/(2)`
at low temperature and `(5R)/(2)` at higher temperature explain .

Explanation

To explain the difference in the molar heat capacity at constant volume (C_v) values of helium (He) and hydrogen (H₂) at various temperatures, we need to consider the molecular structure and degrees of freedom of these gases.

### Step-by-Step Solution:

1. **Understanding C_v**:
- C_v is the molar heat capacity at constant volume, which indicates how much heat is required to raise the temperature of one mole of a substance by one degree Celsius at constant volume.

2. **C_v of Helium (He)**:
...