What is the orientation of the armature loop in a simple ac generator when the following is true. Explain your reasoning for each situation, and discuss why they do not occur at the same orientation.
(a) the value of the emf is a minimum
(b) the value of the magnetic flux is a minimum
Hi! this is a question on one of my physics study guides but i dont understand it. could anyone explain (a) and (b) for me please? i appreciate it! thank you yahoo physics genuises!!! :]
23. July 2010 at 11:06 pm
The flux Φ = B*A*cos(ωt) and the Emf = -B*A*ω*sin(ωt)
a) The Emf is a minimum (i.e. -B*A*ω) when sin(ωt) = 1 This occurs when the plane of the loop aligns with the magnetic field. At this point the flux is zero.
a) The flux is a minimum (i.e. -B*A) when cos(ωt) = -1. This occurs when the plane of the coil is perpendicular to the field and the positive direction of the coil is anti-parallel to the field. At this point the Emf is zero
Since the sin and cos functions are 90o out of phase, they each peak when the other is zero