Final answer:
A shift in internal timing when a magneto is operating can be attributed to changes in magnetic flux, influenced by alterations in the motion of the spinning magnet, which affects the rate of induced electromotive force.
Step-by-step explanation:
When a magneto is operating, a probable cause for a shift in internal timing could be due to any change in magnetic flux. The magnetic field within the coil changes rapidly due to the spinning magnet, which creates an electromotive force (emf) that is proportional to the rate of change of the magnetic flux.
If the timing of the magnet's rotation shifts or the speed changes, this would alter the rate at which the magnetic field changes, thus affecting the timing of the emf induced. Motion is a significant cause of induction — a process wherein a change in magnetic flux induces an emf that opposes the change. In the case of a magneto, the spinning of a magnet in front of a wire coil induces a sufficiently large voltage to produce a spark across a gap formed by the ends of the wire coil.
Any alteration in this motion could result in a timing shift. As Faraday's experiments showed, changing the angle or the speed at which this motion occurs directly influences the magnetic flux and the resulting emf, which is crucial for the operation of a magneto.