One moving electron when comes closer to other stationary electron, then its kinetic energy and potential energy respectively……and…….

Options

A. increases, increases
B. increases,decreases
C. decreases, increases
D. decreases, decreases

Explanation

To solve the problem of what happens to the kinetic energy and potential energy of a moving electron as it approaches a stationary electron, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Charges**:
- Both electrons have a negative charge. According to Coulomb's law, like charges repel each other.

2. **Consider the Motion of the Moving Electron**:
- As the moving electron approaches the stationary electron, it experiences a repulsive force due to the interaction between the two negative charges.

3. **Analyze Kinetic Energy**:
- The moving electron is initially in motion with a certain kinetic energy (KE). As it gets closer to the stationary electron, the repulsive force acts on it, causing it to slow down.
- Since the electron is losing speed due to this repulsion, its kinetic energy decreases.

4. **Analyze Potential Energy**:
- The potential energy (PE) between two charges is given by the formula:
\[ PE = \frac{k \cdot q_1 \cdot q_2}{r} \]
where \( k \) is Coulomb's constant, \( q_1 \) and \( q_2 \) are the magnitudes of the charges, and \( r \) is the distance between them.
- As the distance \( r \) decreases (the electrons come closer), the potential energy increases because the potential energy is inversely proportional to the distance between the charges.

5. **Apply Conservation of Energy**:
- The total mechanical energy (kinetic + potential) of the system must remain constant (assuming no external forces). Therefore, if the kinetic energy decreases, the potential energy must increase to conserve the total energy.

6. **Conclusion**:
- The kinetic energy of the moving electron decreases, while the potential energy increases as it approaches the stationary electron.

### Final Answer:
- Kinetic Energy: Decreases
- Potential Energy: Increases