Question

A long current carrying conductor is placed in the plane of paper as shown in figure. Find direction of ${B_1}$ and ${B_2}$, magnetic fields at points P and Q respectively.

Answer 1

Hint: Recall that magnetic field is the region around a magnet where its effect can be felt and it exerts its influence. The magnetic field has both magnitude and direction. When a current carrying conductor is placed in a magnetic field, then it experiences a force.

Complete step by step solution:
Step I: The direction of magnetic field in a current carrying conductor can be known by using Right Hand Thumb Rule.
According to this rule, if the current carrying conductor is placed in a magnetic field and is held in the right hand then, the thumb will point towards the direction of flow of current and the curled fingers show the direction of magnetic field due to the current carrying conductor.

Step II: In the given figure, it is given that ${R_1} > {R_2}$
Therefore, at point P the magnetic field is into the plane according to the Right Hand Thumb Rule. Whereas at point Q the magnetic field is outside the plane of the paper using the Right Hand Thumb Rule.

Note: It is to be noted that when a current carrying conductor is placed in a magnetic field, the field exerts a force that has equal magnitude but points in the opposite direction. The conductor experiences a force because the electric current is flowing through the conductor. Due to this electric current, a magnetic field is produced in the conductor. Therefore an electromagnetic field is produced in the conductor. Also the magnetic field can be increased if the current flowing through the conductor is increased.