Exam Question

### (a) Means of Changing Magnetic Flux Associated with a Conductor
Based on Faraday's Law of Electromagnetic Induction, an electromotive force (e.m.f.) is induced in a conductor whenever the magnetic flux linking it changes. The magnitude of this induced e.m.f. is directly proportional to the rate of change of flux linkage ($$ \mathcal{E} = -N \frac{d\Phi_B}{dt} $$). The magnetic flux ($$\Phi_B$$) itself is the product of the magnetic field strength ($$B$$) and the area ($$A$$) perpendicular to the field. Thus, the flux linkage can be changed by altering any of the variables in this relationship. The primary methods are:
1. **Relative Motion between the Conductor and the Magnetic Field:**
* This is the most common method used in electrical generators and motors. By physically moving the conductor through a stationary magnetic field, or moving the magnetic field relative to a stationary conductor, the amount of magnetic flux 'cut' by the conductor changes with time.