What is the charge on an atom if it has 13 protons and 14 electrons?

negative charge,

because atom is made of electrons,protons, and neutrons. Electron is negatively charge, proton is positively charged and neutron is neutral so when the number of protons and electrons are equal it makes the atom neutral in charge, BUT IF

THE ELECTRON IS ADDED IN THE ATOM IT BECOMES NEGATIVELY CHARGED

THE ELECTRON IS REMOVED FROM THE ATOM THEN IT BECOMES POSITIVELY CHARGED

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.