A brass rod 1.020 m long expands 3.0mm when it is heated. Find the temperature change

The low lands i believe

Ithink the answer for this is: an electromagnet is a magnet  with a soft metal core.

In atoms, the electron carries a negative elementary or unit charge; the proton carries a positive charge. the two types of charge are equal and opposite. in an atom of matter, an electrical charge occurs whenever the number of protons in the nucleus differs from the number of electrons surrounding that nucleus.