A particle of mass m and charge q is thrown in a region where uniform gravitational field and electric field are present. The path of particle:

Options

A. straight line
B. ellipse
C. parabola
D. circle

Explanation

To determine the path of a particle of mass \( m \) and charge \( q \) thrown in a region where a uniform gravitational field and an electric field are present, we can analyze the forces acting on the particle.

### Step-by-Step Solution:

1. **Identify the Forces Acting on the Particle**:
- The particle experiences two forces:
- The gravitational force \( F_g = mg \) acting downwards (where \( g \) is the acceleration due to gravity).
- The electric force \( F_e = qE \) acting in the direction of the electric field \( E \) (where \( E \) is the magnitude of the electric field).

2. **Determine the Net Force**:
- The net force \( F_{net} \) acting on the particle can be expressed as the vector sum of the gravitational force and the electric force:
\[ F_{net} = F_e + F_g \]
- Depending on the orientation of the electric field with respect to the gravitational field, the net force will have a specific direction.

3. **Analyze the Direction of the Forces**:
- If the electric field is directed upwards and the gravitational field is directed downwards, the net force will be the difference between the two forces:
\[ F_{net} = qE - mg \]
- If \( qE > mg \), the particle will accelerate upwards; if \( qE < mg \), the particle will accelerate downwards.

4. **Determine the Path of the Particle**:
- Since the net force is constant (both \( mg \) and \( qE \) are constants), the particle will experience constant acceleration.
- According to Newton's first law, if a particle is subjected to a constant net force, it will move in a straight line.

5. **Conclusion**:
- Regardless of the configuration of the electric and gravitational fields, the particle will follow a straight-line trajectory due to the constant net force acting on it.

### Final Answer:
The path of the particle will be a straight line.