There is a current I flowing in a clockwise direction in a square loop of wire that is in the plane of the paper. If the magnetic field is toward the right, and if each side of the loop has length L, the net magnetic torque acting on the loop is:

IBL²

Explanation:

Given that

Current flowing in the wire, is I

Magnetic field towards the right, is B

Length of each side of the loop, is L

Number of windings on the loop, is N

Torque exerted on the wire, is T

The torque, T is usually given by the formula

Torque, T = NBIAsinθ,

and if N = 1 and sinθ = 1 also, then we have

Torque, T = BIA

And we know that Area A from this particular question will be given as = L². If we then substitute A for L², we then have

Torque, T = IBL²

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.