Induced EMF and current

[Kathi201]

A long, straight wire is in the same plane as a wooden, non-conducting loop. The wire carries an increasing current I in the direction shown in the figure (the current is pointing in the left direction).

a. there will be no induced emf and no induced current
b. there will be a counterclockwise induced emf, but no induced current
c. there will be a clockwise induced emf, but no induced current
d. there will be a clockwise induced current in the loop
e. there will be a counterclockwise induced current in the loop

How do you figure out the direction of the emf if you know the direction of the current. The direction of the current is to the left so I believe that means it is moving clockwise. Does that mean that the emf is moving clockwise as well?

[alphysicist]

A long, straight wire is in the same plane as a wooden, non-conducting loop. The wire carries an increasing current I in the direction shown in the figure (the current is pointing in the left direction).

a. there will be no induced emf and no induced current
b. there will be a counterclockwise induced emf, but no induced current
c. there will be a clockwise induced emf, but no induced current
d. there will be a clockwise induced current in the loop
e. there will be a counterclockwise induced current in the loop

How do you figure out the direction of the emf if you know the direction of the current. The direction of the current is to the left so I believe that means it is moving clockwise. Does that mean that the emf is moving clockwise as well?


The answer here will depend on how the figure is drawn. As a first step, think about the B field prodeced by the wire. Which way is that B field passing through the loop? Once you have that, you can apply Lenz's law to find the direction of the induced emf.