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AP EAMCET · PHYSICS · Magnetic Effects of Current

Two circular coils 1 and 2 are made from the same wire. The radius of the first coil is twice that of the second coil. What is the ratio of potential difference applied across them \(V_1 / V_2\), so that the magnetic field at their centre is the same?

  1. A 3
  2. B 4
  3. C 6
  4. D 2
Verified Solution

Answer & Solution

Correct Answer

(B) 4

Step-by-step Solution

Detailed explanation

Magnetic field due to first coil and second coil is same at centre. Then, magnetic field at centre is \[ B=\frac{\mu_0 I_1}{2(2 r)}=\frac{\mu_0 I_2}{2(r)} \Rightarrow \frac{I_1}{I_2}=2...(i) \] As we know that, resistance of the coil is related as \[ R=\rho \frac{l}{A} \] where,…