Rotating Conductor in Magnetic Field · CAP 2010 #Q22
Physics · electromagnetism
Problem
The drawing shows a copper wire (of negligible resistance) bent into a circular shape with a radius of r. The radial section BC is fixed in place, while the copper bar AC sweeps around at an angular speed of ω. The bar makes electrical contact with the wire at all times. The wire and the bar have negligible resistance. A uniform magnetic field exists everywhere, is perpendicular to the plane of the circle, and has a magnitude of B. Which of the following shows the magnitude of the current as a function of θ?
a) [Graph option a]
b) [Graph option b]
c) [Graph option c]
d) [Graph option d]
[Figure: Circular wire with rotating bar AC and fixed section BC, with four different current vs. angle graphs as options]