Question

z sin(e) v=cn 6 Magnetic fields, force on charge and current: 11. Calculate the strength and direction of the net magnetic fields at points 1, 2 and 3 as shown in the diagram below. Point 2 is the mid point ( Answers: At 1 Bnet = 66.7 ut, out of the page; At 2 Bnet = 200 u T, into the page, At 3 Bner = 66.7 ut, out of the page) 1 • 2.0 cm 10 A 2. 4.0 cm 10 A 2.0 cm

Answer 1

Magnetic field at a point at distance 'r' due to current carrying is given as

B = u_oI / 2$\pi$r

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At point 1,

Using right hand rule, field due to upper wire points out of the page and field due to bottom wire points into the page. Let field out of the page be positive and field into the page be negative.

B_net = 4$\pi$e-7 * 10 / 2$\pi$ * 0.02 - 4$\pi$e-7 * 10 / 2$\pi$ * 0.06

B_net = 1e-4 - 3.33e-5

B_net = 6.66e-5 T

B_net = 66.7 uT ( out of the page)

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At point 2

Using right hand rule, field due to upper wire points into of the page and field due to bottom wire points into the page.

B_net = - 4$\pi$e-7 * 10 / 2$\pi$ * 0.02 - 4$\pi$e-7 * 10 / 2$\pi$​​​​​​​ * 0.02

B_net = - 1e-4 - 1e-4

B_net = -2e-4 T

B_net = 200 uT (into the page)

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At point 3

Using right hand rule, field due to upper wire points into of the page and field due to bottom wire points out the page.

B_net = - 4$\pi$e-7 * 10 / 2$\pi$ * 0.06 + 4$\pi$e-7 * 10 / 2$\pi$​​​​​​​ * 0.02

B_net = - 3.33e-5 + 1e-4

B_net = 66.7 uT (out of the page)