RRB Technician 2014 Ques 26
Question: The magnetic field at a distance r from a long wire carrying current i is $ 0.4 $ tesla. The magnetic field at a distance 2 r is
Options:
A) $ 0.2 $ tesla
B) $ 0.8 $ tesla
C) $ 0.1 $ tesla
D) $ 1.6 $ tesla
Show Answer
Answer:
Correct Answer: A
Solution:
- $ B=\frac{{\mu_0}i}{2\pi r}\Rightarrow 0.4=\frac{{\mu_0}i}{2\pi r} $ $ B’=\frac{{\mu_0}i}{2\pi (2r)}=\frac{1}{2}\frac{{\mu_0}i}{2\pi r}=\frac{1}{2}\times 0.4=0.2 $ tesla
BETA
