Torque on a Dipole in Electric Fields

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Questions and Answers

What is the relationship between torque and the angle θ when a dipole is placed in a uniform electric field?

The torque is directly proportional to $sin(θ)$, meaning that it reaches its maximum when θ is 90 degrees.

Explain why the net force on a dipole in a uniform electric field is zero.

The net force is zero because the equal and opposite forces acting on the positive and negative charges cancel each other out.

Describe how torque is calculated for a dipole in an electric field, mentioning the variables involved.

Torque, τ, is calculated using the formula τ = $qE × 2l sin(θ)$, where $qE$ represents the force on each charge, $2l$ is the distance between the charges, and $θ$ is the angle between the dipole and the electric field.

What does the dipole moment p represent, and how is it related to the charges and their separation?

The dipole moment p is given by $p = q × 2l$, representing the strength and direction of the dipole, dependent on the charge magnitude and the separation distance. Signup and view all the answers

How does the concept of torque apply to the motion of a dipole in a uniform electric field?

Torque causes the dipole to undergo rotational motion until it aligns with the electric field, thereby minimizing the potential energy. Signup and view all the answers

Explain how the torque on a dipole in a uniform electric field is calculated.

The torque, τ, on a dipole in a uniform electric field is calculated using the formula τ = qE * 2l * sin θ, where q is the charge, E is the electric field strength, l is the distance between the charges, and θ is the angle between the dipole and the electric field. Signup and view all the answers

What conditions need to be met for a dipole to experience no net force in a uniform electric field?

A dipole experiences no net force in a uniform electric field when the forces acting on each charge are equal and opposite, resulting in a net force of zero. Signup and view all the answers

Discuss the role of the angle θ in the torque equation for a dipole in an electric field.

The angle θ determines the effectiveness of the electric field in producing torque; as θ approaches 90 degrees, sin θ approaches 1, maximizing the torque. Signup and view all the answers

What physical principle allows a dipole to rotate in an electric field despite experiencing no net force?

The physical principle is the creation of a torque due to the opposing forces on the dipole, which, while equal and opposite in net force, produce a rotational effect. Signup and view all the answers

If you increase the distance between the charges of a dipole, what effect does this have on the torque in a uniform electric field?

Increasing the distance between the charges increases the torque, as it is directly proportional to the separation distance (2l) in the torque equation τ = qE * 2l * sin θ. Signup and view all the answers

Study Notes

Dipole in a Uniform Electric Field

A dipole consists of two equal and opposite charges separated by a distance, positioned in a uniform electric field at an angle θ.
Positive charge experiences a force ( F_{+q} = +qE ) while negative charge experiences ( F_{-q} = -qE ).
The net force acting on the dipole is zero because the forces on the charges cancel each other out due to equal magnitude and opposite direction.

Torque on the Dipole

No linear force acts on the dipole despite being in an electric field; the forces balance out.
Torque (( τ )) arises from the difference in forces acting at two distinct points on the dipole.
The formula for torque is ( τ = F \times r ), which can also be expressed as ( τ = qE \cdot 2l \cdot \sin θ ).
This leads to the relationship ( τ = pE \sin θ ), where:
- ( p ) is the dipole moment given by ( p = q \cdot 2l ).

Key Concepts

The angle ( θ ) between the dipole and the electric field influences the torque experienced by the dipole.
Torque leads to rotational motion, aligning the dipole with the electric field direction for potential energy minimization.
The dipole moment (( p )) is a crucial parameter representing the strength and orientation of the dipole in the field.

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Description

This quiz covers the concept of torque on a dipole placed in a uniform electric field. It focuses on the net forces acting on the dipole and provides key equations relating to torque. Understanding these principles is essential for grasping the behavior of dipoles in electric fields.