Along wire is known to have a radius greater than 10.0 mm and less 20 mm, carry a current uniformly distributed over its cross section. if the magnitude of the magnetic field is 3 mt at a point 6.0 mm from the axis of the wire and 1.50 mt at a point 20 mm from the axis, what is the radius of the wire?

Radius = 7.75 mm

Explanation:

magnetic field inside a point in the wire is given as

now we have

now outside wire magnetic field is given as

now we have

now divide above two equations

a small object of mass 3.66 g and charge -17.6 µc is suspended motionless above the ground when immersed in a uniform electric field perpendicular to the ground. what are the magnitude and direction of the electric field?

i believe it is b. what was the cause of the big bang

hope this !