Why is torque P Cross E?

Since ‘qd’ is the magnitude of dipole moment (p), and the direction of dipole moment is from positive to negative charge; torque is the cross product of dipole moment and electric field. If the direction of an electric field is positive, the torque is in the clockwise direction (therefore negative) in the above figure.

What is the relation between torque and electric dipole moment?

An electric dipole in an electric field that is external is subjected to a torque written as τ = pE sin θ where symbol θ is the angle which is between p and E. The torque tends to align the moment of the dipole p in the direction of E.

What is the difference between stable and unstable equilibrium of an electric dipole in external uniform electric field?

Note Stable equilibrium means the lowest potential energy at the equilibrium point. Therefore the stable equilibrium the torque should be zero and the potential energy of the dipole should be minimum. Whereas the unstable equilibrium torque will be zero and the potential energy should be maximum or positive.

What is the formula of electric potential due to a dipole?

Therefore, the electric potential due to an electric dipole at a given point is equal to KPcosθr2−a2cos2θ.

How does a torque affect the dipole in an electric field?

How does a torque affect the dipole in an electric field? The torque tends to align the dipole in the direction of the electric field. The electrostatic force on a small sphere of charge 0.4 μC due to another small sphere of charge –0.8 μc in air is 0.2 N.

What is the effect of torque on dipole in an electric field?

Answer: Even though the two forces on the ends of the dipole cancel as free vectors, they act at different points. This means that they give rise to a torque on dipole. The turning effect of this torque is to reduce the angle q towards zero, and make the dipole moment vector become parallel to the field.

How does torque affect the dipole in an electric field?

When the torque on an electric dipole placed in a uniform electric field is?

Show that the torque on an electric dipole placed in a uniform electric field is. τ =P. ×E.

When the dipole is in unstable equilibrium the magnitude of torque is?

zero
Therefore the stable equilibrium the torque should be zero and the potential energy of the dipole should be minimum. Whereas the unstable equilibrium torque will be zero and the potential energy should be maximum or positive.

On which factor electric potential due to electric dipole depends?

The potential due to a dipole depends on r (distance between the point where potential is calculated and the mid-point of the dipole) and angle between position vector r and dipole moment p. Dipole potential is inversely proportional to square of r.

When the electric potential due to a dipole is zero?

What is the electric potential due to an electric dipole at an equatorial point? Zero, as potential on equatorial point, due to charges of electric dipole, are equal in magnitude but opposite in nature and hence their resultant is zero.

Does an electric dipole always experience a torque when placed in a uniform electric field?

When a dipole is placed in a uniform electric field and dipole vector direction is not parallel to field direction, each chargs of dipole experiences a force. Magnitude of the two forces are equal but in opposite direction. Hence in uniform field, dipole experiences only torque.

What is the torque of a dipole?

Since the force magnitudes are equal and are separated by a distance d, the torque on the dipole is given by: Since dipole moment is given by: And the direction of the dipole moment is from the positive to the negative charge, it can see from the above equation that the torque is the cross product of the dipole moment and electric field.

How do you find the component of force perpendicular to dipole?

Consider a dipole with charges +q and –q forming a dipole since they are a distance d away from each other. Let it be placed in a uniform electric field of strength E such that the axis of the dipole forms an angle θ with the electric field. The components of force perpendicular to the dipole are: θ .

Why is electric field at point P only due to dipole?

Both x-components of electric fields due to the electric dipole lie along the same line (parallel to x-axis) in the same direction and therefore the electric field at the point p is only due to the x-components of electric fields of both charges.

What is the formula for electric dipole moment?

The formula for electric dipole moment for a pair of equal & opposite charges is p = qd, the magnitude of the charges multiplied by the distance between the two.