10. Dan wants to increase the strength of an electromagnet. What should he do? A Decrease the size of iron core B. Increase the tum of wire C. Remove the iron core D. Stop the flow of electricity 11. Which makes an electromagnet work? A Electricity B. Needle C. Pin D. Thumbtacks 12. Why is the wire used in electromagnet coiled? A It has more force. B. It controls the field of attraction. C. It controls the flow of electricity D. It controls the low of electrons. 13. Which of the following will be attracted to an electromagnet? A Pins B. Needles C. Thumbtacks D. All the above 14. How can we strengthen an electromagnet? A Decrease the voltage B. Use small iron core C. Increase the number of tums in the coil D. Put a magnetic substance in the com 15. Which activity uses an electromagnet? A. Cooking B. Lighting a room C. Polishing the floor D. Using a door bell 16. Which can increase the strength of an electromagnet?
