In the diagram ( given below ) the broken lines represents the paths followed by particles W,,X,Y and Z respectively through the constant field E. The numbers below the field represents meters.
In previous question if the particles started from rest and all are positively charge which particles must have been acted upon by a force other than that produced by the electric field.

A. W and Y
B. X and Z
C. X,Y and Z
D. W,X,Y and Z

Options

A. W and Y
B. X and Z
C. X, Y and Z
D. W, X, Y and Z

Explanation

To solve the question, we need to analyze the paths of the particles W, X, Y, and Z in the electric field and determine which particles must have been acted upon by a force other than the electric field.

### Step-by-Step Solution:

1. **Understanding the Motion of Charged Particles in an Electric Field:**
- When a charged particle is placed in an electric field, it experiences a force due to the field. The direction of this force is along the direction of the electric field for positive charges.

2. **Analyzing Particle X:**
- Particle X is observed to be moving in a circular path. For a charged particle to move in a circular path, there must be a centripetal force acting on it. This centripetal force cannot be provided solely by the electric field if the particle is moving in a circular trajectory. Therefore, an external force must be acting on particle X.

3. **Analyzing Particles Y and Z:**
- Particles Y and Z are moving against the direction of the electric field. Since they are positively charged, they would naturally accelerate in the direction of the electric field. If they are moving against it, there must be an external force acting on them to counteract the force due to the electric field. Thus, both particles Y and Z must also be acted upon by an external force.

4. **Analyzing Particle W:**
- Particle W is moving in the same direction as the electric field. Since it started from rest and is moving in the direction of the electric field, it is likely being accelerated by the electric field itself. Therefore, we cannot conclusively say that an external force is acting on particle W.

5. **Conclusion:**
- Based on the analysis, particles X, Y, and Z must have been acted upon by a force other than that produced by the electric field. Therefore, the correct answer is **C. X, Y, and Z**.