Question

The magnetic moment produced in a substance of 1 g is $6\times {10}^{-7}A-m^2$. If its density is $5g/c{m}^3$, then the intensity of magnetisation in A/m will be :

• A. $8.3\times {10}^{-6}$
• B. $3.0$
• C. $1.2\times {10}^{-7}$
• D. $3\times {10}^{-6}$

Answer 1

Answer: (B)

$3.0$

$I=\frac{M}{v}=\frac{M}{mass/density}$
Given mass $=1g={10}^{-3}kg$
and density $=5gc{m}^3$
$=\frac{5\times {10}^{-3}kg}{\left({10}^{-6}\right)m^3}$
$=5\times {10}^{3}kg/m^3$
$I=\frac{6\times {10}^{-7}\times 5\times {10}^3}{{10}^{-3}}=3$