justin loves to make electromagnets in his spare time. he wanted to teach his friend jimmy about what the iron core of an electromagnet does. what is the best explanation?
a) it is a conductor that allows more current to flow through the electromagnet.
b) it produces a magnetic field that adds to the overall magnetic field of the electromagnet.
c) it is an insulator that protects people from getting shocked.
d) it produces a current that passes through the coil.

In the first law of thermodynamics, triangle e=q-w, what does q stand for

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?

The process of a material going through a change of state from a gas to a liquid