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प्रश्न
An electric dipole consists of two opposite charges each of magnitude 1 μC, separated by 2 cm. The dipole is placed in an external electric field of 105 N/C. Calculate the:
- maximum torque experienced by the dipole and
- work done by the external field to turn the dipole through 180°.
उत्तर
Given:
q = 1 μC = 10-6 C, E = 105 N/C, 2l = 2 cm = 2 × 10-2 m
To Find:
τmax = ?, W = ?
We know that, p = q × 2l = 10-6 × 2 × 10-2 = 2 × 10-8 m
- τmax = pE = 2 × 10-8 × 105 = 2 × 10-3 Nm
- Work done by the external field to turn the dipole through 180° is given by,
W = pE(cosθ1 - cosθ2)
∴ W = 2 × 10-8 × 105 × (1 + 1)
∴ W = 4 × 10-3 J
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