L. Choose the Letter of the best answer. 1. Which does not affect the magnetism of an electromagnet? A magnet B. Number of the batteries a C. number of coils D. size of the nail 2. Which makes the force of an electromagnet stronger? A bigger iron nail 0. less battery C. less coil of wire D. more bar magnets 3. What happens when you disconnect an electromagnet from a battery? A. It will explode metals B. It will stop from attracting metals C. It will continue from attracting D. nothing will happen. 4. What material is produced when a coil of wire is wind around an iron nail? A battery B. circuit 5. Magnets are usually made of A. iron C. electromagnet D. magnet 8. plastic C. wood 6. An electric motor uses an electromagnet to change A magnetic fields in the motor magnetic poles in the motor C. mechanical energy to electrical energy t D. electrical energy o mechanical energy 7. An electric current in a wire coil produces B A. another current B. a magnetic field C. a source of voltage D. a generator 8. To strengthen an electromagnet A. decrease the voltage. B. increase the number of turns in a coil. C put a non magnetic substance in the coil. D. all of the above 9. An electromagnet functions when A. You put a bulb into it. B. Electricity flows through it. C. two objects rubbed together D. you use a horseshoe magnet. 10. which of the following is True about electromagnet? A. They don't need a battery 8. They are permanent magnet C. Increasing the number of coils make the electromagnet stronger. D. Increasing the number of batteries makes the electromagnet weaker D. ceramicsDirections False, replace the underlined words to make the statement True. Write the word True if the statement is correct, if the statement is 11 An electromagnet may be produced by making electricity flow through a coil of wire wound around an iron nail. 12 When electricity stops flowing through a coil of wire, the nail continues attracting any metal or magnetic material. 13. An electromagnet can be made stronger by using less coils of wire. 14. The number of dry cells used affects the magnetism 9of an electromagnet. More dry cells mean less magnetism. 15. Electromagnets are permanent magnets that can attract any metal or magnetic material.​