A bar magnet of magnetic moment $5.0\, A m^2$ has poles 20 cm apart. The pole strength would be
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 25 A m
$\text{Given: } M = 5.0\,\text{A·m}^2, \, l = 20\,\text{cm} = 0.20\,\text{m}$
$\text{Magnetic moment: } M = m \times l$
$\Rightarrow m = \frac{M}{l}$
$m = \frac{5.0}{0.20} = 25\,\text{A·m}$
$\text{Answer: } m = 25\,\text{A·m}$