An electric dipole is placed in a uniform electric field. What will be the net electric force on the dipole?

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Ques: An electric dipole is placed in a uniform electric field. What will be the net electric force on the dipole?

Ans: The net force on electric dipole when it is placed in a uniform electric field is “zero”.

Explanation: When an electric dipole is placed in a uniform electric field, the electric field exerts a force on each charge of the dipole. Since the charges in a dipole are of equal magnitude but opposite in sign, the force acting on them also becomes equal in magnitude but opposite in direction.

electric dipole placed in a uniform electric field

Electric dipole placed in a uniform electric field

The force on the positive charge of the dipole is in the direction of the electric field, and the force on the negative charge is in the opposite direction.

As a result, the two forces create a torque on the dipole, which tends to rotate it.
The force on +q is directed to the right and on −q is to the left.
The magnitude of forces are equal as the electric field is uniform. Hence, the net force is always zero.

However, the net electric force on the dipole is always zero because the electric field is uniform and the two forces on the charges are equal and opposite in direction. This means that the electric force on the dipole's center of mass is zero, and the dipole will not experience any translational acceleration in the electric field.

Therefore, the electric dipole experiences only a torque in a uniform electric field, but the net force is always zero.

CBSE CLASS XII Related Questions

1.
A circular coil of 100 turns and radius \( \left(\frac{10}{\sqrt{\pi}}\right) \, \text{cm}\) carrying current of \( 5.0 \, \text{A} \) is suspended vertically in a uniform horizontal magnetic field of \( 2.0 \, \text{T} \). The field makes an angle \( 30^\circ \) with the normal to the coil. Calculate:
the magnetic dipole moment of the coil, and
the magnitude of the counter torque that must be applied to prevent the coil from turning.

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2.
In a Young's double-slit experiment, two waves each of intensity I superpose each other and produce an interference pattern. Prove that the resultant intensities at maxima and minima are 4I and zero respectively.

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3.
Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:

attract with a force \( \frac{F}{2} \)
repel with a force \( \frac{F}{2} \)
repel with a force \( F \)
attract with a force \( F \)

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4.
The magnetic field in a plane electromagnetic wave travelling in glass (\( n = 1.5 \)) is given by \[ B_y = (2 \times 10^{-7} \text{ T}) \sin(\alpha x + 1.5 \times 10^{11} t) \] where \( x \) is in metres and \( t \) is in seconds. The value of \( \alpha \) is:

\( 0.5 \times 10^3 \, \text{m}^{-1} \)
\( 6.0 \times 10^2 \, \text{m}^{-1} \)
\( 7.5 \times 10^2 \, \text{m}^{-1} \)
\( 1.5 \times 10^3 \, \text{m}^{-1} \)

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5.
Nuclides with the same number of neutrons are called:

Isobars
Isotones
Isotopes
Isomers

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Assertion : Photoelectric effect is a spontaneous phenomenon. Reason (R): According to the wave picture of radiation, an electron would take hours/days to absorb sufficient energy to overcome the work function and come out from a metal surface.

Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
Assertion (A) is true, but Reason (R) is false.
Both Assertion (A) and Reason (R) are false.

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An electric dipole is placed in a uniform electric field. What will be the net electric force on the dipole?

CBSE CLASS XII Related Questions

2.
In a Young's double-slit experiment, two waves each of intensity I superpose each other and produce an interference pattern. Prove that the resultant intensities at maxima and minima are 4I and zero respectively.

3.
Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:

4.
The magnetic field in a plane electromagnetic wave travelling in glass (\( n = 1.5 \)) is given by \[ B_y = (2 \times 10^{-7} \text{ T}) \sin(\alpha x + 1.5 \times 10^{11} t) \] where \( x \) is in metres and \( t \) is in seconds. The value of \( \alpha \) is:

5.
Nuclides with the same number of neutrons are called:

6.
Assertion : Photoelectric effect is a spontaneous phenomenon. Reason (R): According to the wave picture of radiation, an electron would take hours/days to absorb sufficient energy to overcome the work function and come out from a metal surface.

Similar Physics Concepts

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An electric dipole is placed in a uniform electric field. What will be the net electric force on the dipole?

CBSE CLASS XII Related Questions

2.In a Young's double-slit experiment, two waves each of intensity I superpose each other and produce an interference pattern. Prove that the resultant intensities at maxima and minima are 4I and zero respectively.

3.Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:

4.The magnetic field in a plane electromagnetic wave travelling in glass (\( n = 1.5 \)) is given by \[ B_y = (2 \times 10^{-7} \text{ T}) \sin(\alpha x + 1.5 \times 10^{11} t) \] where \( x \) is in metres and \( t \) is in seconds. The value of \( \alpha \) is:

5.Nuclides with the same number of neutrons are called:

6.Assertion : Photoelectric effect is a spontaneous phenomenon. Reason (R): According to the wave picture of radiation, an electron would take hours/days to absorb sufficient energy to overcome the work function and come out from a metal surface.

Similar Physics Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

2.
In a Young's double-slit experiment, two waves each of intensity I superpose each other and produce an interference pattern. Prove that the resultant intensities at maxima and minima are 4I and zero respectively.

3.
Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:

4.
The magnetic field in a plane electromagnetic wave travelling in glass (\( n = 1.5 \)) is given by \[ B_y = (2 \times 10^{-7} \text{ T}) \sin(\alpha x + 1.5 \times 10^{11} t) \] where \( x \) is in metres and \( t \) is in seconds. The value of \( \alpha \) is:

5.
Nuclides with the same number of neutrons are called:

6.
Assertion : Photoelectric effect is a spontaneous phenomenon. Reason (R): According to the wave picture of radiation, an electron would take hours/days to absorb sufficient energy to overcome the work function and come out from a metal surface.