 So now we're ready to look at the last part of the front side of this worksheet. And so that's the calculation question. It refers to a long straight wire, which is carrying a current, and it wants to know about the magnitude of the magnetic field at a certain distance away. We had our general bioservart law that we talked about at the top of the worksheet, but now we go to the special case. And if you haven't watched the video for the special case equation, you want to go back and do that. The one that I'm using here is this equation, where we're finding the magnitude of the magnetic field, depending on the current, and A stands for the distance away from that wire. So from that equation, we can then figure out what our knowns are. Now remember, this mu-naught constant, which is the permeability of free space, can be written either as an exponent or in terms of the 4 pi. We're given the value for the current, and we're given the value for A for how far away you are from that current. So now it's just a matter of plugging in those values. Now remember, when you plug this into your calculator, you're going to want to use the parentheses for that entire region there on the bottom. I'm not going to do the math for you here. You'll need to plug that into your calculator. And you also need to remember your units. If you take a close look at how these units work out and the video for the long straight line, you should be able to get that figured out.