Magnetic Effects Of Current Question 128
Question: A wire carrying current I and other carrying 2I in the same direction produces a magnetic field B at the mid point. What will be the field when 2I wire is switched off [AFMC 2005]
Options:
A) B / 2
B) 2B
C) B
D) 4B
Show Answer
Answer:
Correct Answer: C
Solution:
When two parallel conductors carrying current I and 2I in same direction, then magnetic field at the midpoint is $ B=\frac{{\mu_{0}}2l}{2\pi r}-\frac{{\mu_{0}}I}{2\pi r}=\frac{{\mu_{0}}I}{2\pi r} $ When current 2I is switched off then magnetic field due to conductor carrying current I is $ B=\frac{{\mu_{0}}I}{2\pi r} $ .
BETA
