JEE Mains · Physics · STD 12 - 5. Magnetism and matter
The coercivity of a magnet is \(5 \times 10^3 \mathrm{~A} / \mathrm{m}\). The amount of current required to be passed in a solenord of length \(30 \mathrm{~cm}\) and the number of turns \(150\) , so that the magnet gets demagnetised when inside the solenoid is _______ A.
- A \(10\)
- B \(12\)
- C \(15\)
- D \(20\)
Answer & Solution
Correct Answer
(A) \(10\)
Step-by-step Solution
Detailed explanation
\(\mathrm{H}_{\mathrm{c}}=\frac{\mu_{\mathrm{v}} \mathrm{ni}}{\mu_{\mathrm{o}}}\) \(5 \times 10^3=\frac{150}{30} \times 100 \times \mathrm{i}\) \(\frac{50}{5}=\mathrm{i}\) \(\mathrm{I}=10\)
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