An electric dipole in a uniform electric field experiences (When it is placed at an angle `theta` with the field)

Options

A. Both a torque and a net force
B. Only a force but no torque
C. Only a torque but no net force
D. No torque and no net force

Answer

To solve the problem of what happens to an electric dipole placed at an angle θ in a uniform electric field, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Electric Dipole**:
An electric dipole consists of two equal and opposite charges, +Q and -Q, separated by a distance 'd'. The dipole moment (p) is defined as \( p = Q \cdot d \).

2. **Visualizing the Electric Field**:
Draw a uniform electric field represented by parallel lines. The direction of the electric field (E) is usually indicated from positive to negative.

3. **Placing the Dipole in the Field**:
Position the dipole in the electric field such that it makes an angle θ with the direction of the electric field.

4. **Calculating Forces on the Charges**:
- The positive charge (+Q) experiences a force \( F_+ = Q \cdot E \) in the direction of the electric field.
- The negative charge (-Q) experiences a force \( F_- = -Q \cdot E \) in the opposite direction of the electric field.

5. **Finding the Net Force**:
The net force acting on the dipole is the vector sum of the forces on the two charges:
\[ F_{\text{net}} = F_+ + F_- = Q \cdot E - Q \cdot E = 0 \]
Thus, the net force acting on the dipole is zero.

6. **Calculating the Torque**:
The torque (τ) experienced by the dipole in the electric field can be calculated using the formula:
\[ \tau = p \cdot E \cdot \sin(\theta) \]
where \( p \) is the dipole moment and \( E \) is the electric field strength. Since the dipole is not aligned with the field, it experiences a torque that tends to align it with the field.

7. **Conclusion**:
Since the net force on the dipole is zero and there is a non-zero torque acting on it, we conclude that the dipole experiences only a torque and no net force when placed at an angle θ in a uniform electric field.

### Final Answer:
The correct option is **C: only a torque but no net force**.