Plastic is used to cover electrical cords. this indicates that plastic is a(n)
a. conductor
b. plasma
c. form of energy
d. insulator

D) INSULATORS

Explanation:

electrical chord are the medium to travel electric current

so here it is always covered so that it is not dangerous to surrounding.

So in order to cover it we know that we need a material which will not allow that current to pass through the body of the person who is holding the wire

so such material which do not allow the electric current to pass through them is known as insulators

so here correct answer would be

D) INSULATORS

explanation: magnetic pole, region at each end of a magnet where the external magnetic field is strongest. the south-seeking pole, or any pole similar to it, is called a south magnetic pole. unlike poles of different magnets attract each other; like poles repel each other.

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.