An electric dipole consists of two equal and opposite point charges ±q separated by distance 2a. Its dipole moment magnitude is
A{'text': 'p = q × a', 'label': 'A'}
B{'text': 'p = q² × 2a', 'label': 'B'}
C{'text': 'p = q × 2a', 'label': 'C'}
D{'text': 'p = 2q / a', 'label': 'D'}
Answer & Solution
Correct answer: C. {'text': 'p = q × 2a', 'label': 'C'}
1. Dipole moment p is defined as charge × separation.
2. For dipole of ±q separated by 2a: p = q × (2a) = 2aq.
3. Direction of p is from −q to +q.
4. SI units: coulomb-metre (C·m).
_Source: NCERT Class 12 Physics, Ch 1 "Electric Charges and Fields", §1.7_
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