How is an electromagnet different from a bar magnet?
a) only a bar magnet has a magnetic field.
b) only an electromagnet attracts materials made of iron.
c) an electromagnet is temporary and is magnetic when a current flows through a wire wrapped around the core.
d) a bar magnet is a temporary and is only magnetic when a current flows through a wire wrapped around the core.

Atriangle with equal sides of length 10 cm has -2.5-nc charged objects at each corner. part a determine the direction of the electrical force exerted on the object at the top corner due to the two objects at the horizontal base of the triangle. determine the direction of the electrical force exerted on the object at the top corner due to the two objects at the horizontal base of the triangle. horizontally rightward vertically downward vertically upward horizontally leftward