Ques. What is a molecule?
Ans. A molecule is composed of two or more atoms.
Ques. What is the behaviour of these minute bodies?
Ans. They are perpetually in motion, vibrating with incredible velocities.
Ques. Why at this point are definitions of energy and of matter most useful?
Ans. Because, as stated, all electric action is an exhibition of energy, and energy must act through matter as its medium.
Ques. What is the difference between electricity and magnetism?[8]
Ans. The ultimate nature of neither is known. There are, however, some differences. To sustain a current of electricity requires energy. To sustain magnetism requires no energy. A current of electricity is always accompanied by a magnetic field of peculiar form. Magnetism alone cannot produce electricity. Electricity can do work; but magnetism cannot in the same sense—and alike with electricity, neither can it exist without contact with matter.
Ques. How is energy transmitted from one part of a material substance to another?
Ans. Gradually and successively. It requires a medium and also time.