What to read after Physics Exam-builder for HKDSE?

Book 4 deals with the topics on the section "electricity and magnetism", which carries a substantial weight on the HKDSE syllabus and examination. Electricity plays an important role in the modern world in every sector of human activities. Every person nowadays has to use electrical appliances every day. Some general knowledge about electrical safety is essential.

As a subject, learning this topic at DSE level lays the foundation for further studies in the field of science, engineering, and other innovative technological development. It is customary to name this section of the syllabus as "electricity and magnetism". In fact, there is a close relationship between them. An electric current produces a magnetic field, and magnetic fields interact to produce magnetic forces in motors. A changing magnetic field produces an induced e.m.f. which is the basic physics principle underlying the production of electricity using a.c. generators in power stations. The magnetism of a permanent magnet is in fact due to atomic currents caused by orbiting and spinning electrons. Hence except for static charges, the name electromagnetism is used to describe various phenomena relating currents, changing currents, magnetic fields and changing magnetic fields.