Flux density
A 0.40 m wire carrying 2.5 A feels 0.30 N at 90°. Find B.
Current force
B=0.60 T, I=4.0 A, L=0.20 m and θ=30°. Find F.
Moving charge
Find force on an electron at 4.0×10⁶ m s⁻¹ perpendicular to 0.25 T.
Circular motion
Explain why magnetic force changes direction but not speed.
Velocity selector
E=8.0×10⁴ V m⁻¹ and B=0.40 T. Find v.
Current field
Describe the field inside a long solenoid.
Parallel wires
Why do same-direction currents attract?
Induction
120 turns experience a flux change of 3.0 mWb in 0.060 s. Find emf.
Lenz's law
Explain the minus sign in Faraday's law.