Magnetism Question 290
Question: A Rowland ring of mean radius 15 cm has 3500 turns of wire wound on a ferromagnetic core of relative permeability 800. What is the magnetic field B in the core for a magnetising current of l .2 amp?
Options:
A) 4.48 T
B) 2.48 T
C) 5.48 T
D) 3.12T
Show Answer
Answer:
Correct Answer: A
Solution:
[a] Where u is the permeability of the core and $ {\mu _{r}} $ is the relative permeability Now, $ {\mu _{0}}=4\pi \times {{10}^{-7}},TM{{A}^{-1}} $ , $ {\mu _{r}}=800 $ and $ n=\frac{N}{2\pi r}=\frac{3500}{2\pi r}=\frac{3500}{2\pi \times 0.15,}{{m}^{-1}} $
$ B=\mu ,n,I={\mu _{0}}{\mu _{r}},n,I $
$ \
Therefore ,,,,,B=\frac{(4\pi \times {{10}^{-7}})\times 800\times 3500\times 1.2}{(2\pi \times 0.15)}=4.48,T $
BETA
