What is the angle between the electric dipole moment and the electric field strength due to it on the equatorial line

Options

A. `0^(@)`
B. `90^(@)`
C. `180^(@)`
D. None of these

Answer

To find the angle between the electric dipole moment and the electric field strength due to it on the equatorial line, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Electric Dipole**: An electric dipole consists of two equal and opposite charges, +q and -q, separated by a distance 'd'. The electric dipole moment (p) is defined as \( p = q \cdot d \) and points from the negative charge to the positive charge.

**Hint**: Recall the definition of an electric dipole moment and its direction.

2. **Identify the Equatorial Line**: The equatorial line is the line that is perpendicular to the dipole axis and lies in the plane that bisects the dipole. This is the region where we need to analyze the electric field.

**Hint**: Visualize the dipole and the equatorial plane to understand where the electric field is being calculated.

3. **Determine the Electric Field on the Equatorial Line**: The electric field (E) due to an electric dipole at a point on the equatorial line is directed away from the dipole. The contributions to the electric field from both charges at any point on the equatorial line will cancel out in the direction along the dipole axis, resulting in a net electric field that is perpendicular to the dipole moment.

**Hint**: Consider the contributions of the electric fields from both charges and how they combine on the equatorial line.

4. **Analyze the Directions**: The electric dipole moment points from the negative charge (-q) to the positive charge (+q). However, on the equatorial line, the electric field points in the opposite direction to the dipole moment. This means that the dipole moment and the electric field are anti-parallel.

**Hint**: Visualize the directions of both the dipole moment and the electric field to see how they relate to each other.

5. **Calculate the Angle**: Since the electric dipole moment and the electric field on the equatorial line are in opposite directions, the angle between them is 180 degrees.

**Hint**: Remember that anti-parallel vectors have an angle of 180 degrees between them.

### Final Answer:
The angle between the electric dipole moment and the electric field strength due to it on the equatorial line is **180 degrees**.