JEE Advanced2014PhysicsMagnetic Effects of CurrentActual
Paragraph: The figure shows a circular loop of radius a with two long parallel wires (numbered 1 and 2 ) all in the plane of the paper. The distance of each wire from the centre of the loop is d . The loop and the wires are carrying the same current I . The current in the loop is in the counterclockwise direction if seen from above. Question: When d a but wires are not touching the loop, it is found that the net magn
Options
- Acurrent in wire 1 and wire 2 is the direction PQ and RS, respectively and h ≈ a
- Bcurrent in wire 1 and wire 2 is the direction PQ and SR, respectively and h ≈ a
- Ccurrent in wire 1 and wire 2 is the direction PQ and SR, respectively and h ≈ 1.2   a
- Dcurrent in wire 1 and wire 2 is the direction PQ and RS, respectively and h ≈ 1.2   a
Correct answer
C. current in wire 1 and wire 2 is the direction PQ and SR, respectively and h ≈ 1.2   a
Step-by-step solution
The net magnetic field at the given point will be zero if. B → w i r e s = B → l o o p ⇒ 2 μ 0 I 2 π a 2 + h 2 × a a 2 + h 2 = μ 0 I a 2 2 a 2 + h 2 3 2 ⇒ h ≈ 1.2   a