What is the requirement for a core to be used in an electromagnet? a. it must be able to be increased. b. it cannot be magnetized. c. it must be an ion. d. it must be able to be magnetized.

Answer : It must be able to be magnetized ( D )

Explanation :

A soft ion bar is taken and several turns of an insulated copper wire are wound over it on passing an electric current on the wire the ion bar becomes a magnet, such a magnet is called electromagnet.The wire turns are usually wound around a core made up of a magnetic force or ferromagnetic material like iron; the core concentrates the magnetic flux and makes a lot of powerful magnet.

D. It must be able to be magnetized.

Explanation:

An electromagnet is a device formed by an iron core surrounded by a solenoid (coil). When an electric current passes through the coils of the coil, a magnetic field is created, which causes the elementary magnets of the iron core to orientate themselves, thus being magnetized and, consequently, with the property of attracting other ferromagnetic materials. For this reason, we can say that in order for a nucleus to be used on an electromagnet it must be magnetizable.

d. air pressure decreases as altitude increases.