Questions and answers cover animals, geography, science, and historyHow does a junk-yard magnet work? Powerful magnets, which can be switched on and off, are used to move heavy pieces of metal around junk yards. These magnets, called electromagnets, work because an electric current flowing along aanbsp;...
|Title||:||The Usborne Book of Questions and Answers|
|Author||:||P. Dowswell, M. Claridge, A. Smith|
|Publisher||:||Edc Pub - 1993|