Question

find the magnitude of the resultant magnetic field at the point P and Q both situated at a distance of 2 cm from the wire in same horizontal plane?

Answer 1

@ash2326 hlp me out.

Answer 2

Hi @Ruchi. Do you know Ampere's law?

Answer 3

no can u xplain it?

Answer 4

OK, For example take a wire, suppose it's carrying current inside the drawing page. Do you get this part?

Answer 5

ok this cross indicate the direction of current inside.

Answer 6

by right hand thumb rule may i right?

Answer 7

Yes, good. By right hand thumb rule, we can predict the direction of magnetic field. It'll be in the following direction Is this ok?

Answer 8

yes

Answer 9

So, I'll write Ampere's Law now, then I'll explain.
It states that
\[\oint \vec B. \vec dl= \mu_0 \times I\]
the closed loop is a loop around the wire. I is the current penetrating through the loop's surface.

Answer 10

Ok, I'll explain now.

Answer 11

Let's take a loop around the wire, it can be square, circle or rectangle. Anything would work. But let's take circle here

Answer 12

Now attach a surface to the loop, it can be open or closet. I'll attach a open surface

Answer 13

Assume this is a plastic bag and the wire is going inside. So the current which is penetrating is I.

Do you get this part?