Welcome to the Official Guide to No Safety in Numbers. A biological bomb has just been discovered in the air ducts of a busy suburban mall. At first nobody knows if it's even life threatening, but then the entire complex is quarantined, people start getting sick, supplies start running low, and there's no way out. This is the ultimate guide to the book that started the series!
So that we can use the computer, watch the television and fans. And other things that need electricity. Electromagnets are used in electrical devices like electric fan, motor, door-bell, electric buzzers, washing machines, etc., whenever strong magnetic fields are needed to be pâ¦roduced, electromagnets are used. These are used in electrically operated relay switches, and in nuclear research laboratories for directing charged particles.
Types of Electromagnetic Radiation. There are waves of energy and light moving all around us in the form of TV and audio transmissions, gamma radiation from space, and heat in the atmosphere. Scientists call them all electromagnetic radiation. The waves of energy are called electromagnetic (EM) because they have oscillating electric and magnetic fields. Scientists classify them by their frequency or wavelength, going from high to low frequency (short to long wavelength).