A motorcyclist is making an electric vest that, when connected to the motorcycle's 12 V battery, will warm her on cold rides. She is using 0.25-mm-diameter copper wire, and she wants a current of 4.3 A in the wire. What length wire must she use?

8.2 m

Explanation:

We are given that

Potential difference=

Diameter=

Radius=

Current= I=4.3 A

Resistivity of copper wire of

We have to find the length of wire must she use.

We know that

Using the formula

ohm

Using

Hence,  she must use the length of wire =8.2 m

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.