Question

Consider two current-carrying wires, separated by a distance d =2.1 cm, as shown in the figure. The left wire is directed out of the page with current I1, and the right wire is directed into the page with current I2. The point P is a distance d from both wires, so the wires and the point form an equilateral triangle.

Part (a) 

If both wires are carrying a current of 4.5 A, what is the magnitude of the magnetic field, in tesla, at point P?

Answer 1

A)

Net field, B = sqrt[B1^2 + B2^2 + 2B1 B2 cos(theta)]

B = (u0/2 pi d) sqrt[I1^2 + I2^2 - 2 I1 I2 cos(theta)]

B = (4 pi x 10^-7/2 pi x 0.021)[4.5^2 + 4.5^2 - 2 x 4.5^2 cos(60)]

B = (9.52 x 10^-6)(4.5)

B = 4.28 x 10^-5 T

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