Which statement about electromagnet is true
it doesn’t function without a source of current
the core is made from a non magnetic material
it used moving magnets to create an electric field
it creates a permanent and strong magnetic field

It doesn’t function without a source of current

Explanation:

In an electromagnet, the magnetic field is generated by an electric current in a coil of wire which reinforces an iron core. But when the electric current applied on the mentioned core is disconnected, it immediately loses its magnetization. This also means that the intensity of the magnetic field can be controlled (increased or decreased) by changing the intensity of the electric current flowing through the nucleus.  

That is why an electromagnet does not work without electric current.

Explanation:

An electromagnet is defined as a magnet where its magnetic field is generated by an electrical current.

A simple form of an electromagnet is coil of wire wrapped around an iron core. The iron material helps to intensity the magnetic field.

Additonally, the strength of the magnetic field depends directly on the amount of current.

Therefore, the right answer is the first choice, because an electromagnet won't work without a current.

answer: option c.

explanation:

the bal will not change its velocity.