00:01
All right, so let's say we have two conducting rails with a movable bar that is moving to the left, the speed v, and there is a resistor here with a resistance r.
00:10
And then everywhere in this region, there is a magnetic field going out of the page as indicated by these dots.
00:21
And we're told that the length of this bar, l, is 0 .385 meters.
00:28
The magnetic field strength is 0 .658 tesla, and the bar is moving with a speed of 5 .9 meters a second.
00:45
And the first question, oh, sorry, in the resistor itself has a resistance of 4 .3 oms.
00:52
So question a asks, what is the direction of the induced current in this? well, if we look at how the flux is changing, as the bar moves to the left, so the area that the current loop encloses is decreasing, right? so like delta a is negative.
01:15
And so that's going to produce a decreasing flux, and hence an emf, of course.
01:21
And the current induced in this is going to oppose the decreasing flux.
01:25
So it's going to want to produce an increasing flux, if that makes sense.
01:30
And so it's also going to produce a field or i mean a yeah a magnetic field that like opposes this and so for a current like that to work you need the current to go in the counterclockwise direction and then part b if you take a look at it part b asks basically what's the power of this system because there's a force required to move this so the power is going to be the force times the velocity...