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JEE Mains · Physics · STD 12 - 4. Moving charges and magnetism
The electric current in a circular coil of \(2\) turns produces a magnetic induction \(B _{1}\) at its centre. The coil is unwound and is rewound into a circular coil of \(5\) turns and the same current produces a magnetic induction \(B _{2}\) at its centre.The ratio of \(\frac{ B _{2}}{ B _{1}}\) is.
- A \(\frac{5}{2}\)
- B \(\frac{25}{4}\)
- C \(\frac{5}{4}\)
- D \(\frac{25}{2}\)
Answer & Solution
Correct Answer
(B) \(\frac{25}{4}\)
Step-by-step Solution
Detailed explanation
\(B=\frac{N \mu_{0} 1}{2 R}\) \(B_{1}=\frac{N_{1} \mu_{0} i}{2 R_{1}}\) For \(N _{2}=5\) Radius of coil \(= R _{2}=\frac{ N _{1} \times R _{1}}{ N _{2}}\) \(B _{2}=\frac{ N _{2} \mu_{0} i }{ R _{2}}\)…
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