Question

A magnetising field of 1600 A-m^–1 produces a magnetic flux of 2.4 × 10^–5Wb in an iron bar of cross-sectional area 0.2 cm². The susceptibility of an iron bar is

• A. 298
• B. 596
• C. 1192
• D. 1788

Answer 1

Answer: (B)

596

Answer 2

By using $B = \mu H = \mu _ { 0 } \mu _ { r } H$ and $\mu _ { r } = \left( 1 + \chi _ { m } \right)$

⇒ $\mu _ { r } = \frac { B } { \mu _ { 0 } H } = \frac { \phi } { \mu _ { 0 } H A }$

$\mu _ { r } = \frac { 2.4 \times 10 ^ { - 5 } } { \left( 4 \pi \times 10 ^ { - 7 } \right) \times 1600 \times \left( 0.2 \times 10 ^ { - 4 } \right) }$= 596.8.

Hence $\chi _ { m } = 595.8 \approx 596$