course phys202
There was only two questions because the third was a university question
1. A circular loop of diameter 9.6 cm in a 1.10 T field perpendicular to the plane of the loop; loop is removed in .15 s. What is the induced EMF?-The induced EMF is the average rate of change of the magneticflux with time. The equation for this is flux= m. field * area
- = 1.10 T * (pi * .048 m)^2 = .00796 T m^2.
- Since the flux is reduced to 0 when the loop is removed the magnitude is .0080 and divide it by the time .15 s= .053volts
2. 320-loop square coil 21 cm on a side, .65 T mag field. How fast to produce peak 120-v output? How many cycles per second are required to produce a 120-volt output, and how did you get your result?
- We can figure the output by finding the average rate of flux change. The area of a single coil is 21cm^s and the magnetic field is .65 T and there are 320 coils.
- Perpendicular= .65T* (.21 m)^2 * 320 = 19.2 T m^2.
- Then the average mag. Field= change of flux/t
- == 9.17T m^2 / (1/4 t_cycle) = 36.7 T m^2 / t_cycle.
- We then solve for t with the voltage being 120V/sqrt2 and get .432s
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