At ordinary temperatures, the molecules of an ideal gas have only translational and rotational kinetic energies. At high temperatures they may also have vibrational energy.
As a result of this, at higher temperature

Options

A. `C_(v)=3R//2` for monatomic gas
B. `C_(v) gt 3R//2` for monatomic gas
C. `C_(v) lt 5R//2` for diatomic gas
D. `C_(v) gt 5R//2` for diatomic gas

Explanation

To solve the question regarding the kinetic energies of an ideal gas at ordinary and high temperatures, we will analyze the behavior of monoatomic and diatomic gases separately.

### Step-by-Step Solution:

1. **Understanding Kinetic Energy in Gases**:
- At ordinary temperatures, the molecules of an ideal gas exhibit translational and rotational kinetic energies.
- Translational kinetic energy is due to the movement of the gas molecules in space, while rotational kinetic energy arises from the rotation of the molecules around their axes.

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