A long solenoid with 1000 turns/m has a core material with relative permeability 500 and volume 103 cm3. 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.
Answer (integer)
250
Solution
$${{\Delta M} \over M} = {{\Delta \mu } \over \mu } = {{250} \over {500}} = {1 \over 2}$$<br><br>$\Rightarrow$ ${1 \over 2} = {x \over {499}} \Rightarrow x \simeq 250$
About this question
Subject: Physics · Chapter: Magnetic Effects of Current · Topic: Biot-Savart Law
This question is part of PrepWiser's free JEE Main question bank. 96 more solved questions on Magnetic Effects of Current are available — start with the harder ones if your accuracy is >70%.