The figure below shows two parallel conducting rails, oriented vertically, conne
ID: 1309886 • Letter: T
Question
The figure below shows two parallel conducting rails, oriented vertically, connected to each other at the top by a wire with a resistance R. A conducting metal rod is oriented horizontally and is in contact with the two vertical rails. The horizontal rod has a length L = 50.0 cm and mass 35.0 g. The rod is released from rest at location A and begins to fall through a region of uniform magnetic field indicated by the shaded area in the figure. When the rod reaches point B, there is an induced current of 1.85 A flowing to the right in the rod, and the rod is moving downward with an acceleration of magnitude 7.85 m/s2.
What are the direction and magnitude of the magnetic field in the shaded region?
Magnituted in Teslas. Direction is either upward, downward, to the left, to the right, into the page or our of the page.
Explanation / Answer
By Faraday's law. direction of field is into the page.
If, the magnitude is B,
Equating force on the rod using Newton's second law,
BIL = F=m(g-f)
or, B*1.85*0.5= 35/1000*(9.81 - 7.85)
or, B=0.074162 Tesla