Mastering Physics: CH 21 H x C a Search https://session masteringphysics.com 770
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Mastering Physics: CH 21 H x C a Search https://session masteringphysics.com 77056565 Help I Close PHYS 112 003 Resources CH 21 HW8 PSS 21.1 Faraday's Law e previous l 3 of 7 l next Problem-Solving Strategy 21.1 Faraday's law SETUP Learning Goal: 1. To calculate the rate of change of magnetic flux, you first have to understand what is making the flux change. Is the conductor To apply Problem-Solving Strategy 21.1 Faraday's law. moving? Is it changing orientation? Is the magnetic field changing? Remember that it is not the flux itself, but its rate of change. that counts. A closely wound rectangular coil of 80 turns has dimensions 25.0 cm by 40.0 cm. The plane of the coil is SOLVE rotated from a position in which it makes an angle of 37.0 2. Use Faraday's law E IAg/Atl to find the induced em nd the change in flux A and the change in time At. Don't forget to degrees with a magnetic field of 1.10 T to a position perpendicular to the field. The rotation takes 0.0600 s. multiply by the number N of turns in the coil when you calculate the change in flux. What is the average emf Einduced in the coil? 3. Use Lenzs law to determine the direction of the induced currents and emfs. REFLECT 4. The shape of the coil doesn't matter, it can be circular, rectangular, or some other shape. Only the total rate of change of flux through the coil and its number of turns are significant. SET UP Before writing any equations, organize your information and draw appropriate diagrams. Part A Which of the following quantities from the equation for magnetic flux changes in this situation? Check all that apply. O magnitude of the magnetic field area of the coil orientation of the coil with respect to the magnetic field direction Submit My Answers Give UpExplanation / Answer
Emf induced is the change in flux over time,
= -N/t
where = BAcos
The initial flux is = (1.1T)(.25m*.4m)*cos(90-37) = 0.066Tm2
Note, you use the cos(90-37) because they indicate the angle is made between the PLANE and the B field; you need the angle between the AREA and the B field, and the area points normal to the plane (making a 90 degree angle.
The final flux is = (1.1T)(0.25m*0.4m) = 0.11Tm2
Once again, since the PLANE is perpendicular, the normal is parallel to the B field, so all of the B field is going through the area.
Now, if t = 0.06s,
= (80)(0.11Tm2 - 0.066Tm2)/(0.06s)= 58.6V induced.
You can ignore the negative; it only implies which side of the coil is at a higher potential