A straight wire 0.2 m long carries 4 A at right angles to a uniform field of 0.5 T. What is the force on the wire?

Answer and explanation

Correct answer: D. 0.4 N, from F = BIL with the wire at right angles to the field

  1. Step 1: Use for a wire perpendicular to the field. Step 2. N. Answer: 0.4 N. Why not the others: 0.8 N doubles the product; 10 N divides instead of multiplying; 0.1 N leaves out the current.

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