Một dây dẫn đặt trong không khí có dòng điện I = 12A chạy qua, được gấp thành hình vuông cạnh a = 10cm. Xác định vectơ cường độ từ trường tại tâm O của hình vuông.

The net magnetic field ta the center of square is.

Explanation:

Current, I = 12 A , side ,a = 10 cm =  0.1 m

Let the magnetic field due to the one side is B.

The magnetic field is given by

Net magnetic field at the center of the square is

B' = 4 B

c) up is the direction the magnetic force is acting on the charge.

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