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KCET · Physics · Magnetic Effects of Current

A solenoid is 1 m long and 4 cm in diameter. It has five layers of windings of 1000 turns each and carries a current of 7 A . The magnetic field at the centre of the solenoid is

  1. A \(0.4396 \times 10^{-5} \mathrm{~T}\)
  2. B \(4.396 \times 10^{-2} \mathrm{~T}\)
  3. C \(43.96 \times 10^{-2} \mathrm{~T}\)
  4. D 439.6 T
Verified Solution

Answer & Solution

Correct Answer

(B) \(4.396 \times 10^{-2} \mathrm{~T}\)

Step-by-step Solution

Detailed explanation

\(\ell=1 \mathrm{~m} ; \mathrm{r}=2 \mathrm{~cm} ; \mathrm{N}=5000 ; \mathrm{t}=7 \mathrm{~A} ; \sin \theta \approx 1\)

\(\mathrm{B}=\frac{\mu_0 \mathrm{Ni}}{\ell} \sin \theta\)
\(\begin{aligned} & B=\frac{4 \pi \times 10^{-7} \times 5000 \times 7 \times 1}{1} \\ & B=4.396 \times 10^{-2} \mathrm{~T}\end{aligned}\)