A particle moves in a circle of radius R. In half the period of revolution its displacement is ………… and distance covered is ………. .

Explanation

To solve the problem, we need to determine the displacement and distance covered by a particle moving in a circle of radius R after completing half of its period of revolution.

### Step-by-Step Solution:

1. **Understanding the Motion**:
- The particle is moving in a circular path with a radius \( R \).
- Half of the period of revolution means the particle has moved from one point on the circle to the point directly opposite it.

2. **Calculating the Distance Covered**:
- The distance covered by the particle in half a revolution is half the circumference of the circle.
- The circumference \( C \) of a circle is given by the formula:
\[ C = 2\pi R \]
- Therefore, the distance covered in half the revolution is:
\[ \text{Distance} = \frac{C}{2} = \frac{2\pi R}{2} = \pi R \]

3. **Calculating the Displacement**:
- Displacement is defined as the shortest distance between the initial and final positions of the particle.
- When the particle moves half the circle, its initial position and final position are at opposite ends of the diameter.
- The displacement, which is the length of the diameter, is given by:
\[ \text{Displacement} = 2R \]

### Final Answers:
- **Displacement**: \( 2R \)
- **Distance Covered**: \( \pi R \)