A rectangular loop with a sliding connector of length ℓ=1.0 m is in a uniform magnetic field B=2 T perpendicular to the loop. The connector resistance is r=2 Ω. Two resistors 6 Ω and 3 Ω are connected as shown. Find the external force (N) required to keep the connector moving at constant speed v=2 m/s.

Question

G1 Physics · Accepted Answer

For a moving conductor, ε=∫(v⃗×B⃗)·dℓ⃗. Combine this with Ohm’s law and Lenz’s law where required. The result is 2.