Question 312: Magnetism and Matter

Question

A long solenoid with 1000 turns/m has a core material with relative permeability 500 and volume 10
3
cm
3
. If the core material is replaced by another material having relative permeability of 750 with same volume maintaining same current of 0.75 A in the solenoid, the fractional change in the magnetic moment of the core would be approximately $$\left( {{x \over {499}}} \right)$$. Find the value of x.

Accepted Answer

$${{\Delta M} \over M} = {{\Delta \mu } \over \mu } = {{250} \over {500}} = {1 \over 2}$$
$$ \Rightarrow $$ $${1 \over 2} = {x \over {499}} \Rightarrow x \simeq 250$$

Magnetism and Matter

Integer / Numeric Answer Type