A student investigates the magnetic force acting on a straight, current-carrying wire placed perpendicular to a uniform magnetic field.
The student changes the current in the wire and the strength of the magnetic field.
Which two changes together must decrease the magnetic force on the wire?
increasing the current and increasing the magnetic field strength
increasing the current and decreasing the magnetic field strength
decreasing the current and increasing the magnetic field strength
decreasing the current and decreasing the magnetic field strength
275 exam-style questions on CIE IGCSE Physics 4.5 Electromagnetic effects, covering 4.5.1a Electromagnetic induction, 4.5.1b Direction of an induced e.m.f., 4.5.2 The a.c. generator, 4.5.3a Magnetic effect of a current and its applications, 4.5.3b Strength and direction of the field around wires and solenoids, 4.5.4a Force on a current-carrying conductor, 4.5.4b Force on beams of charged particles, 4.5.5 The d.c. motor, 4.5.6a Construction and operation of a transformer, 4.5.6b Turns ratio and current in a transformer, and 4.5.6c High-voltage transmission of electricity. Each one has a worked solution and a mark scheme showing where the marks go.