00:01
So in this question, basically we have a current carrying wire of infinite size and at a point which is exactly, let's say this point is speed, which is exactly 25 centimeters from the wire, or you can call it 25 into 10 rest to the power minus 2 meter from the wire.
00:22
So we need to find the magnetic field, the magnitude of magnetic field.
00:26
So we know that the magnetic field around the wire is in the form of circular loops basically.
00:33
So that way magnetic field here would be entering into the plane of the paper.
00:39
So this is the way to actually see the direction of magnetic field.
00:44
And in case if the direction of magnetic field is not very clear to you, you can do one thing.
00:48
You can put your thumb in direction of current and curl the fingers of your right hand.
00:53
So take your right hand, put the thumb of the right hand in direction of current.
00:56
And then curl your fingers of the right hand.
00:59
You'll see at point b your fingers are trying to enter into the plane of the board basically, or a plane of the screen.
01:05
Your hand is trying to enter into the plane of the screen, basically.
01:09
And from that, you can see the magnetic field is acting inwards...