Question

The amplitude of alternating e.m.f depends on?

Answer 1

Electromotive force (e.m.f) is the electric potential generated by any non-electric sources (like magnetic effect or batteries and cells). Represented$\varepsilon$ , electromotive force is measured in terms of electric potential $\left( {V,\,\,Volt} \right)$ . Any battery or cell works on converting any form of energy (specifically chemical) into electric energy which is measured as e.m.f; hence we can say e.m.f is the amount of work done to produce a unit electric charge.
$\varepsilon = \dfrac{{Joules}}{{Coulombs}}$

Complete step by step solution:
Alternating current is the current produced on application of unstable or varying potential. If the applied potential to produce the electric current is altering with time i.e. changes its instance with time, it generates alternating current. And the potential generated by alternating current whose magnitude alternate sinusoidal manner forms alternating emf.
$E = \varepsilon = {E_0}\sin \left( {\omega t} \right)\,\,\,.........({\text{instantaneous value of a}}{\text{.emf)}}$
Where,
${E_0} = \,{\text{Peak value of a}}{\text{.emf}}$
Peak value of emf denotes the maximum potential generated but when we talk about amplitude of emf, it is defined by the peak value of alternating current produced by this emf in any direction. It is denoted by:
${I_0} = {\text{Peak value of A}}{\text{.C}}{\text{.}} = {\text{Amplitude of a}}{\text{.emf}}$
${I_0} = \dfrac{{{E_0}}}{R}$
As we have noticed, the process of manufacture of emf requires non-electric sources i.e. amount of voltage or resistance are the factors that are applicable only for the processing of current. These factors will not define the amount of current produced. The amount of potential generated by a non-electric source will generate specific current. If the generator produces less potential, so alternating current will be less.
The factor on which our amplitude of emf or ac current depends is material of the generator. As the material will only define the alternate potential generated, that can be utilized to generate alternative current.

Note:
If we provide a constant similar potential, it will generate direct current (DC). If the potential applied, varies with time hence current generated will be alternative. Devices such as batteries which provide a constant potential will give dc current. In the case of a hanging magnet, the magnet keeps on changing direction of its polarity which will generate potential and give rise to alternating current.