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प्रश्न
Depict the orientation of an electric dipole in (a) stable and (b) unstable equilibrium in an external uniform electric field. Write the potential energy of the dipole in each case.
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उत्तर
- The dipole is in stable equilibrium when it is parallel to the electric field (i.e., the angle between the dipole moment and the electric field is 0°).
- When the dipole is aligned anti-parallel to the electric field (i.e., the angle between the dipole moment and the electric field is 180°, then the dipole is in unstable equilibrium.
For stable equilibrium (θ = 0°)
Potential energy U = -pE cosθ
U = -pE
For unstable equilibrium (θ = 180°)
Potential Energy U = -pE cosθ
U = pE
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| (i) | (ii) | (iii) |
What is the net force acting on an electric dipole when it is placed in a uniform electric field?
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What must an external agent do to rotate a dipole slowly in a uniform electric field?
What reference angle is chosen to simplify the potential energy formula for a dipole, and why?
How does the potential energy of a dipole change as it rotates from being antiparallel (θ = 180°) to being parallel (θ = 0°) with the electric field?
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