SCIENCE
Choose the correct answer. Write only the letter.
1. Which statement is TRUE about an electromagnet?
A. An electromagnet is a permanent magnet.
C. Electricity is not needed to make an electromagnet
B. It is a temporary magnet.
D. A small dry cell makes a strong electromagnet
2.Which of the following is NOT a factor affecting the strength of an electromagnet?
A. Number and diameter of dry cells (battery) B. Core materials
C. Plastic caps
D. Number of turns or coils
3.An electric motor or generator uses an electromagnet to change
A. magnetic fields in the motor
B. Magnetic size in the motor
C. Mechanical energy to electrical energy
D. Electrical energy to mechanical energy
4.Which of these increase the strength of electromagnets?
1.
increase the number of coil
increase the number of dry cell (battery)
decrease the number of dry cell (battery)
IV. decrease the number of coil
A. I and III
B. I and II
C. II and III
D. III and IV
5. What happens when you disconnect an electromagnet from a battery?
A. It will explode.
B. It will continue from attracting metals.
C. It will stop from attracting metals. D. Nothing will happen.​