COMEDK · Physics · 21. Magnetic Effects of Current
A long solenoid has 20 turns \(\mathrm{cm}^{-1}\). The current necessary to produce a magnetic field of \(20 \mathrm{mT}\) inside the solenoid is approximately
- A \(1 \mathrm{~A}\)
- B \(2 \mathrm{~A}\)
- C \(4 \mathrm{~A}\)
- D \(8 \mathrm{~A}\)
Answer & Solution
Correct Answer
(D) \(8 \mathrm{~A}\)
Step-by-step Solution
Detailed explanation
The magnetic field \(B\) inside a long solenoid is given by the formula \(B = \mu_{0} n I\), where \(n\) is the number of turns per unit length and \(I\) is the current. Given values are: \(B = 20 \text{ mT} = 20 \times 10^{-3} \text{ T}\)…
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