An electric dipole of dipole moment p is lying along uniform electric field E. Calculate the work done in rotating the dipole by 90 degrees.

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Ques: An electric dipole of dipole moment p is lying along uniform electric field E. Calculate the work done in rotating the dipole by 90 degrees.

Ans: The work done in rotating the dipole by 90 degrees when dipole moment is lying along uniform electric field is “pE”.

Explanation: The potential energy of an electric dipole in a uniform electric field is given by an expression: U = -pEcosθ.

where p is the dipole moment,
E is the electric field strength,
θ is the angle between the dipole moment and the electric field.

Initially, the dipole moment is aligned with the electric field, so θ = 0, and the potential energy is:

U1 = -pEcos0 = -pE

When the dipole is rotated by 90 degrees, the angle between the dipole moment and the electric field becomes θ = 90 degrees, and the potential energy becomes:

U2 = -pEcos90 = 0

The change in potential energy is then equal to the work done

Work Done = ΔU = U2 - U1 = 0 - (-pE) = pE

electric dipole of dipole moment p is lying along uniform electric field E

Therefore, the potential energy of the dipole in rotating it by 90 degrees is pE.

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An electric dipole of dipole moment p is lying along uniform electric field E. Calculate the work done in rotating the dipole by 90 degrees.

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1.
If Bohr’s quantization postulate (angular momentum \( = \frac{nh}{2\pi} \)) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why, then, do we never speak of quantization of orbits of planets around the Sun? Explain.

2.
Assertion (A) : The mass of a nucleus is less than the sum of the masses of the constituent nucleons. Reason (R) : Energy is absorbed when the nucleons are bound together to form a nucleus.

3.
Write the expression for the magnetic field due to a current element in vector form. Consider a 1 cm segment of a wire, centered at the origin, carrying a current of 10 A in positive x-direction. Calculate the magnetic field \( \mathbf{B} \) at a point \( (1 \, \text{m}, 1 \, \text{m}, 0) \).

4.
If both the number of protons and the neutrons are conserved in each nuclear reaction, in what way is mass converted into energy (or vice versa) in a nuclear reaction? Explain.

5.
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:

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An electric dipole of dipole moment p is lying along uniform electric field E. Calculate the work done in rotating the dipole by 90 degrees.

CBSE CLASS XII Related Questions

1. If Bohr’s quantization postulate (angular momentum \( = \frac{nh}{2\pi} \)) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why, then, do we never speak of quantization of orbits of planets around the Sun? Explain.

2.Assertion (A) : The mass of a nucleus is less than the sum of the masses of the constituent nucleons. Reason (R) : Energy is absorbed when the nucleons are bound together to form a nucleus.

3.Write the expression for the magnetic field due to a current element in vector form. Consider a 1 cm segment of a wire, centered at the origin, carrying a current of 10 A in positive x-direction. Calculate the magnetic field \( \mathbf{B} \) at a point \( (1 \, \text{m}, 1 \, \text{m}, 0) \).

4. If both the number of protons and the neutrons are conserved in each nuclear reaction, in what way is mass converted into energy (or vice versa) in a nuclear reaction? Explain.

5.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:

Similar Physics Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

1.
If Bohr’s quantization postulate (angular momentum \( = \frac{nh}{2\pi} \)) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why, then, do we never speak of quantization of orbits of planets around the Sun? Explain.

2.
Assertion (A) : The mass of a nucleus is less than the sum of the masses of the constituent nucleons. Reason (R) : Energy is absorbed when the nucleons are bound together to form a nucleus.

3.
Write the expression for the magnetic field due to a current element in vector form. Consider a 1 cm segment of a wire, centered at the origin, carrying a current of 10 A in positive x-direction. Calculate the magnetic field \( \mathbf{B} \) at a point \( (1 \, \text{m}, 1 \, \text{m}, 0) \).

4.
If both the number of protons and the neutrons are conserved in each nuclear reaction, in what way is mass converted into energy (or vice versa) in a nuclear reaction? Explain.

5.
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: