Magnetic Effects Of Current Question 69
Question: The earth’s magnetic induction at a certain point is $ 7\times {{10}^{-5}}Wb/m^{2}. $ This is to be annulled by the magnetic induction at the centre of a circular conducting loop of radius 5 cm. The required current in the loop is [MP PET 1999; MP PMT 2002]
Options:
A) 0.56 A
B) 5.6 A
C) 0.28 A
D) 2.8 A
Show Answer
Answer:
Correct Answer: B
Solution:
$ \frac{{\mu_{0}}}{4\pi }\times \frac{2\pi i}{r}=H\Rightarrow \frac{({{10}^{-7}})\times 2\times 3.142\times i}{0.05}=7\times {{10}^{-5}} $
$ \therefore ,i=\frac{7\times 0.05\times {{10}^{-5}}}{2\times 3.142\times {{10}^{-7}}}=\frac{35}{2\times 3.142}=5.6 $ amp
BETA
