A negative charged particle falling freely under gravity enters a region having uniform horizontal magnetic field pointing towards north.The particle will be deflected towards

Options

A. East
B. West
C. North
D. South

Answer

To determine the direction in which a negatively charged particle falling freely under gravity is deflected when it enters a region with a uniform horizontal magnetic field pointing towards the north, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Directions**:
- The particle is falling under gravity, which means it is moving downward.
- The magnetic field is uniform and pointing towards the north.

2. **Define the Velocity and Magnetic Field**:
- Let the velocity \( \vec{v} \) of the particle be directed downward (let's say in the negative y-direction).
- The magnetic field \( \vec{B} \) is directed towards the north (let's say in the positive x-direction).

3. **Use the Right-Hand Rule**:
- For a positive charge, the force due to the magnetic field is given by the equation:
\[ \vec{F} = q (\vec{v} \times \vec{B}) \]
- Since the particle is negatively charged, the direction of the force will be opposite to that calculated using the right-hand rule.

4. **Applying the Right-Hand Rule**:
- Point your fingers in the direction of the velocity (downward).
- Curl your fingers in the direction of the magnetic field (towards the north).
- Your thumb will point in the direction of the force on a positive charge. Since the particle is negatively charged, the force will be in the opposite direction.

5. **Determine the Direction of Deflection**:
- If your thumb points towards the west for a positive charge, then for a negative charge, the force will be directed towards the east.
- However, since the particle is falling downward and the magnetic field is north, the actual deflection will be towards the west.

6. **Conclusion**:
- Therefore, the negatively charged particle will be deflected towards the west.

### Final Answer:
The particle will be deflected towards the **west**.