STANDARDPhysics-Magnetic Effects of Current
STANDARD Physics Force on a Current-Carrying Conductor MCQ Question
Type: MCQ-numerical-Medium
A 2.5 m long straight wire having mass of 500 g is suspended in mid air by a uniform horizontal magnetic field B. If a current of 4 A is passing through the wire then the magnitude of the field is (Take g = 10 m s⁻²)
A
0.5 T
B
0.6 T
C
0.25 T
D
0.8 T
Correct Answer
Option A
Detailed Explanation
The force due to the magnetic field must balance the gravitational force. Using F = IBl sin θ and setting θ = 90°, we have mg = IBl. Solving for B gives B = mg / (Il) = (0.5 × 10) / (4 × 2.5) = 0.5 T.
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