Moving Charges And Magnetism Ques 51
51. The magnetic induction at a point $P$ which is at a distance of $4 $ $cm$ from a long current carrying wire is $10^{-3} $ $T$. The field of induction at a distance $12 $ $cm$ from the current will be
[1990]
(a) $3.33 \times 10^{-4} $ $T$
(b) $1.11 \times 10^{-4} $ $T$
(c) $3 \times 10^{-3} $ $T$
(d) $9 \times 10^{-3} $ $T$
Show Answer
Answer:
Correct Answer: 51.(a)
Solution:
- (a) $B=\frac{\mu_0 I}{2 \pi r} \Rightarrow B \propto \frac{1}{r}$
As the distance is increased to three times, the magnetic induction reduces to one third. Hence,
$B=\frac{1}{3} \times 10^{-3}$ tesla $=3.33 \times 10^{-4}$ tesla
BETA
