AC electricity can be easily transformed into higher or lower voltages making it more versatile than DC electricity. Since the frequency of AC electricity can be precisely controlled, it is used in motors that require accurate speed, such as clocks and tape recorders. Syllabus Motors use the effect of forces on current-carrying conductors in magnetic fields. The relative motion between a conductor and magnetic field is used to generate an electrical voltage. Generators are used to provide large scale power production in isolated areas and as a backup in emergency situations.
Transformers allow generated power to be either increased or decreased before it is used.
Motors are used in industries and the home usually to convert electrical energy into more useful forms of energy. By the beginning of the twentieth century, many of the pieces of the physics puzzle seemed to be falling into place. The wave model of light had successfully explained interference, diffraction and the wavelengths at the extremes of the visible spectrum had been estimated. The invention of a pump that would evacuate tubes to 10 -4 atmospheres allowed the investigation of cathode rays. X-rays would soon be confirmed as electromagnetic radiation and patterns in the periodic table appeared to be nearly complete.