In this example, we use Phi = BA cos phi to solve for the strength of a magnetic

Question

In this example, we use Phi = BA cos phi to solve for the strength of a magnetic field. A plane surface with area 2.6 cm^2 is placed in a uniform magnetic field that is oriented at an angle of 30 degree to the surface. (a) What is the angle phi? (b) If the magnetic flux through this area is 0.96 mWb, what is the magnitude of the magnetic field? Shows our sketch. As defined earlier, phi is the angle between the direction of B and a line normal to the surface, so phi = 60 degree (not 30 degree) Because B and phi are the same at all points on the surface, we can use Phi_B = BA cos phi. We solve for B, remembering to convert the area to square motors: B = Phi_B/A cos phi = 9.6 times 10^-6 Wb/(2.6 times 10^-4 m^2) (cos 60 degree) = 7.4 The flux through the surface depends on its angle relative to B. Knowing this angle and the flux per unit area, we can find the magnitude of the magnetic field For the same B and A, find the angle phi at which the flux would have one third the value given above (i.e, the angle phi at which Phi_B = 3.2 times 10^-4 Wb)

Explanation / Answer

given flux

flux = 3.2 * 10^-4 Wb

B = 7.4 T

A= 2.6 * 10^-4 m^2

flux = BA cos theta

theta =cos^-1 ( flux/ BA)

= cos^-1 ( 3.2 * 10^-4 Wb/7.4 ( 2.6 * 10^-4 m^2)

=80.42 degree

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.