The magnetic field produced by a long straight current-carrying wire is a) inversely proportional to the current in the wire and proportional to the distance from the wire. b) inversely proportional to both the current in the wire and the distance from the wire. c) proportional to both the current in the wire and the distance from the wire d) proportional to the current in the wire and inversely proportional to the distance from the wire. e) independent of both the current in the wire and the distance from the wire.

The magnetic field produced by a long straight current-carrying wire is directly proportional to the current in the wire and inversely proportional to the distance from the wire.

Explanation:

The magnetic field produced by a long straight current-carrying wire is given by :

............(1)

Where

= permeability of free space,

I = current flowing in the wire

d = distance from wire

From equation (1), it is clear that the magnetic field produced by a long straight current-carrying wire is directly proportional to the current flowing and inversely proportional to the distance from the wire. So, the correct option is (d).

prolly a beacuse the momentuem the car has increases while going down hill