A 1 m long metal rod XY completes the circuit shown. The magnetic field is 0.15 T, the circuit resistance is 5 Ω and the rod moves at 4 m s⁻¹. The force required to maintain constant speed i $s ______$ × 10⁻³ N.

Question

G1 Physics · Accepted Answer

Motional emf: ε = Blv = 0.15×1×4 = 0.60 V Current: I = ε/R = 0.60/5 = 0.12 A Magnetic force on the rod: F = BIl = 0.15×0.12×1 = 0.018 N = 18×10⁻³ N Final value: 18

A 1 m long metal rod XY completes the circuit shown. The magnetic field is 0.15 T, the circuit resistance is 5 Ω and the rod moves at 4 m s⁻¹. The force required to maintain constant speed i s ______ × 10⁻³ N.