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Question:

A wire of mass 100g, length 1m, and current 5A is balanced in mid-air by a magnetic field B. Find the value of B.

0.2 T

0.1 T

0.5 T

0.6 T

Solution:

F = BiL = mg → B × 5 × 1 = 0.1 × 10 → B = 2/10 = 0.2T. Therefore, B = 0.2T