b. electrons c. metal a. Current 1. Written Test A. Directions: Read each item carefully, write the letter of the correct answer on the blank provided 1. It is a cylindrical coil of wire in which a magnetic field is generated by passing a current a. Solenoid 2. It is a device made temporarily magnetic by electricity flowing through a call of wire around an iron nail b. electromagnet c. appliance 3. Which of the following devices make use of electromagnets? a. Electric buzzer b. telephone c. both a and b 4. What makes an electromagnet stronger? When electrons in an electric current do not move When current is stopped or switched off When the number of turns in the coll of wire is increased, adding more dry cells and using a core with a bigger diameter 5. What do you call the ability of the material to attract certain metals resulting from the motions of electrons in atoms? a. affection b. magnetism c. demagnetized 6. What happens when a part of an electromagnetis disconnected? It loses its magnetism b. The electromagnet becomes a permanent magnet It will continue attracting non-metals 7. When the current is stopped or switched off, the solenoid no longer works and can be described as a. Demagnetized b. paralyzed c. magnetized 8. The strength of an electromagnet depends on three factors. Which factor does the statement below relers to? More coits of wiro adds more force to the electromagnet. Number of turns in coil b. Current flowing in a coil C. Length of air gap between poles 9. Which does not affect the magnetism of an electromagnet? Number of coils b. number of batteries c. number of non-metal objects 10. Common magnets attract objects made of iron, cobalt or nickel a. Plastic b. metal c. Insulators a.
