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Physics · PYQ NEET UG 2023
हिन्दीA wire carrying a current \( I \) along the positive \( x \)-axis has length \( L \). It is kept in a magnetic field \( \vec{B} = (2\hat{i} + 3\hat{j} - 4\hat{k})\text{ T} \). The magnitude of the magnetic force acting on the wire is :
Correct answer · Option 3
\( 5\text{ }IL \)
Explanation
Magnetic force \( \vec{F} = I(\vec{L} \times \vec{B}) \). Here \( \vec{L} = L\hat{i} \) and \( \vec{B} = 2\hat{i} + 3\hat{j} - 4\hat{k} \). \( \vec{F} = IL(\hat{i} \times (2\hat{i} + 3\hat{j} - 4\hat{k})) = IL(3\hat{k} + 4\hat{j}) \). Magnitude \( F = IL\sqrt{3^2 + 4^2} = 5IL \).
