Question

Choose the correct sketch of the magnetic field lines of a circular current loop shown by the dot ? and the cross ?.

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

The Correct Option is A

To understand the correct sketch of the magnetic field lines of a circular current loop, we need to consider the behavior of the magnetic field generated by the current-carrying conductor.

When a current passes through a circular loop, magnetic field lines are produced in the loop's vicinity. The direction of these magnetic field lines can be determined using the right-hand rule. According to this rule, if you curl the fingers of your right hand in the direction of the current flow, your thumb points in the direction of the magnetic field inside the loop.

In a circular loop carrying current, the magnetic field lines are concentric circles around each part of the wire, but they appear to emerge from one face of the loop and enter the other. Therefore, they form closed loops. The side from which the field lines appear to come out (north pole) will show dots (representing field lines coming out), and the side where they enter (south pole) will show crosses (representing field lines going in).

Let's analyze the options given:

• Option 1: Depicts field lines correctly using the dot (?) to indicate fields emerging out and the cross (?) to indicate fields going into the loop. This matches the expected pattern for a loop with current flow, where lines emerge from the north and enter the south pole.
• Option 2, 3, and 4: These do not adequately represent the description provided by the right-hand rule, either misplacing the dots and crosses or incorrectly depicting the direction of the field lines.

Thus, the correct diagram that represents the magnetic field lines produced by a current-carrying circular loop is:

This correctly uses the dot to show where the field emerges from one face of the loop and the cross to indicate where it enters back, accurately representing the magnetic field configuration for a circular coil.