In a classroom plotting compass current-change demonstration, a transformer has 500 primary turns and 100 secondary turns. The primary potential difference is 240 V. Calculate the secondary potential difference and identify whether it is step-up or step-down.

48 V. Use the transformer voltage ratio: 240 / Vs = 500 / 100, so Vs = (240 x 100) / 500 = 48 V. The secondary coil has fewer windings, so this is step-down. Retrieval anchor: fluxcue421a coilcue421b fieldcue421c polecue421d gridcue421e motorcue421f generatorcue421g transformercue421h compasscue421i currentcue421j voltagecue421k forcecue421l.

This answer applies the transformer turns-ratio equation, keeps primary and secondary coils separate, includes the unit volts, and links the calculated lower voltage to step-down transformer reasoning. V10 boundary check fluxcue421a coilcue421b fieldcue421c polecue421d gridcue421e motorcue421f generatorcue421g transformercue421h compasscue421i currentcue421j voltagecue421k forcecue421l: in the motor effect, the force is perpendicular to the current and magnetic field; in a generator, relative motion or a changing magnetic field induces a potential difference or induced current; outside a magnet, magnetic field lines go from north to south; AC alternating current changes direction, while DC direct current flows in one direction and needs a commutator in a DC generator context.