PHYS 1112 Module 10.2

Force and Torque on a Current Loop

Magnetic Force on a Current-Carrying Loop

Continuing the discussion about the magnetic force on a current carrying wire, we will now look at what happens if we take a wire and bend it into a loop. We’re going to bend the wire into the shape of a rectangle because it makes the math easier. Then we will put that loop in a uniform magnetic field.

Using the RHR, determine the direction of the magnetic force on each side of the loop.

Using the RHR, determine the direction of the magnetic force on each side of the loop.
What is the direction of the force on side 1 of the loop?

Check your answer: E. into the page

Using the RHR, determine the direction of the magnetic force on each side of the loop.
What is the direction of the force on side 2 of the loop?

Check your answer: G. no force

Using the RHR, determine the direction of the magnetic force on each side of the loop.
What is the direction of the force on side 3 of the loop?

Check your answer: F. out of the page

Using the RHR, determine the direction of the magnetic force on each side of the loop.
What is the direction of the force on side 4 of the loop?

Check your answer: G. no force

Practice!

See if you can use the RHR and your understanding of magnetic fields and forces to answer this:

Practice 10.2.1
A rectangular loop carrying a current is placed in between two bar magnets. The direction of the current in the loop is denoted with an arrow. Looking at it from the side view, how will the loop move?

Check your answer: C. rotate clockwise