## GCE A-Level Physics Syllabus

## Chapter 18: Alternating Current

## Chapter Topics:

Characteristics of alternating currents

Transformers

Rectification with a diode

## Question Bank:

## Learning Objectives:

(a) Show an understanding of and use the terms period, frequency, peak value and root-mean-square (r.m.s.) value as applied to an alternating current or voltage.

(b) Deduce that the mean power in a resistive load is half the maximum (peak) power for a sinusoidal alternating current.

(c) Represent an alternating current or an alternating voltage by an equation of the form x = x₀ sin ωt

(d) Distinguish between r.m.s. and peak values and recall and solve problems using the relationship Iᵣₘₛ = Iₒ/√2 for the sinusoidal case.

(e) Show an understanding of the principle of operation of a simple iron-core transformer and recall and solve problems using Nₛ / Nₚ = Vₛ /Vₚ = Iₚ / Iₛ for an ideal transformer.

(f) Explain the use of a single diode for the half-wave rectification of an alternating current.