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AP EAMCET · PHYSICS · Magnetic Effects of Current

The magnetic field at the centre of a long solenoid having 400 turns per unit length and carrying a current ' \(i\) ' is \(6.24 \times 10^{-2} \mathrm{~T}\). The magnetic field at the centre of another long solenoid having 200 turns per unit length and carrying a current \(\frac{' i^{\prime}}{2}\) is

  1. A \(1.56 \times 10^{-2} \mathrm{~T}\)
  2. B \(2.4 \times 10^{-2} \mathrm{~T}\)
  3. C \(26 \times 10^{-2} \mathrm{~T}\)
  4. D \(2.6 \times 10^{-2} \mathrm{~T}\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(1.56 \times 10^{-2} \mathrm{~T}\)

Step-by-step Solution

Detailed explanation

\(B = \mu_0 n i\) \(B_1 = \mu_0 (400) i = 6.24 \times 10^{-2} \mathrm{~T}\) \(B_2 = \mu_0 (200) \left(\frac{i}{2}\right) = \mu_0 (100) i\) \(B_2 = \frac{100}{400} B_1 = \frac{1}{4} (6.24 \times 10^{-2} \mathrm{~T})\) \(B_2 = 1.56 \times 10^{-2} \mathrm{~T}\)