COMEDK · Physics · 21. Magnetic Effects of Current
The ratio of the magnetic fields at the centre of a circular coil carrying current to that at a point whose distance is half of the radius of the coil is
- A \(2 \sqrt{5}: 8\)
- B \(5 \sqrt{5}: 8\)
- C \(5 \sqrt{5}: 4\)
- D \(2 \sqrt{5}: 4\)
Answer & Solution
Correct Answer
(B) \(5 \sqrt{5}: 8\)
Step-by-step Solution
Detailed explanation
The magnetic field due to a circular coil carrying current at its axis is \[ B_{x}=\frac{\mu_{0}}{4 \pi} \cdot \frac{2 \pi N i r^{2}}{\left(x^{2}+r^{2}\right)^{3 / 2}} \quad \text{...(i)} \] At centre of coil,…
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