Q9. A molecule of a substance has a permanent electric dipole moment of magnitude 10⁻³¹ Cm. A mole o

Q: What is the correct answer for CUET UG Physics Q9?

The correct answer is D. Dipole moment of each molecule = 10⁻³⁰ cm (Note: Question states 10⁻³¹ Cm). As 1 mole of the substance contains 6 × 10²³ molecules. Total dipole moment of all the molecules P = 6 x 10²³ x 10⁻³⁰ Cm = 6 x 10⁻⁷ Cm. Initial potential energy Uᵢ = -pEcos θ = -6 x 10⁻⁷ x 10⁸ cos 0° = -6 J. Final potential energy U_f = -6 x 10⁻⁷ x 10⁸ x cos 60° = -3 J. Work done by field = -(Change in potential energy) =

Q: Q9. A molecule of a substance has a permanent electric dipole moment of magnitude 10⁻³¹ Cm. A mole of this substance is 100% polarised by applying a strong electrostatic field of magnitude 10⁸ Vm⁻¹.…

The correct answer is D. Dipole moment of each molecule = 10⁻³⁰ cm (Note: Question states 10⁻³¹ Cm). As 1 mole of the substance contains 6 × 10²³ molecules. Total dipole moment of all the molecules P = 6 x 10²³ x 10⁻³⁰ Cm = 6 x 10⁻⁷ Cm. Initial potential energy Uᵢ = -pEcos θ = -6 x 10⁻⁷ x 10⁸ cos 0° = -6 J. Final potential energy U_f = -6 x 10⁻⁷ x 10⁸ x cos 60° = -3 J. Work done by field = -(Change in potential energy) =

Q: What are the options for this CUET UG Physics question?

A. -9 J · B. -3 J · C. 9 J · D. 3 J

Question

Q9. A molecule of a substance has a permanent electric dipole moment of magnitude 10⁻³¹ Cm. A mole of this substance is 100% polarised by applying a strong electrostatic field of magnitude 10⁸ Vm⁻¹. The direction of field is suddenly changed by all angle of 60°. Find the heat released by substance in aligning its dipoles along the new direction of the field. [Take 1 mole = 6 x 10²³ molecules]

FirstInTest · Accepted Answer

Dipole moment of each molecule = 10⁻³⁰ cm (Note: Question states 10⁻³¹ Cm). As 1 mole of the substance contains 6 × 10²³ molecules. Total dipole moment of all the molecules P = 6 x 10²³ x 10⁻³⁰ Cm = 6 x 10⁻⁷ Cm. Initial potential energy Uᵢ = -pEcos θ = -6 x 10⁻⁷ x 10⁸ cos 0° = -6 J. Final potential energy U_f = -6 x 10⁻⁷ x 10⁸ x cos 60° = -3 J. Work done by field = -(Change in potential energy) = -[(-3)-(-6)] = 3 J. Heat released by substance is equal to the work done by the field, which is 3 J.

Answer

-9 J

Answer

-3 J

Answer

9 J

Answer

3 J

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