Answer: F = qvB sin(theta).
- A F = qvB
- B F = qv + B
- C F = qvB sin(theta)
- D F = qvB cos(theta)
Correct answer: C. F = qvB sin(theta)
Explanation: F = qvB sin(theta) where theta is angle between v and B. Maximum when v is perpendicular to B (sin90=1).
The magnetic field around a long straight current-carrying wire forms concentric circles, with direction given by the right-hand rule (point thumb along I, fingers curl in the direction of B).
Concept context
Magnetic force on moving charges and currents, the Biot-Savart law, Ampere's law, and the cyclotron - how electric currents create and respond to magnetic fields.