How does the strength of a magnetic field around a wire vary?

By pointing one's right thumb along the direction of the current, the direction of the magnetic field can by found by curving one's fingers around the wire. The strength of the magnetic field depends on the current I in the wire and r, the distance from the wire.

answer: d. a cme increases the amount of energy in the solar wind

explanation:

coronal mass ejections, also called cmes, are large clouds of plasma and magnetic field that erupt from the sun. only when the cloud is aimed at earth will the cme hit earth and therefore cause impacts. high-speed solar wind streams come from areas on the sun known as coronal holes.