Two long current carrying conductors are placed parallel to each other at a distance of 8 cm between them. The magnitude of magnetic field produced at mid-point between the two conductors due to current flowing in them is 300μT. The equal current flowing in the two conductors is :
(A)30 A in the same direction.
(B)30 A in the opposite direction.✓ Correct
(C)60 A in the opposite direction.
(D)300 A in the opposite direction.
Answer: (B)
Solution
For the fields to add at the midpoint, the currents must flow in opposite directions.
Magnetic field at midpoint from both wires: B=2×2πrμ0I
where r=4 cm =4×10−2 m (half the separation).
300×10−6=2π×4×10−22×4π×10−7×I
3×10−4=4×10−22×10−7×I
I=2×10−73×10−4×4×10−2=30 A
Answer: (B) 30 A in the opposite direction.
JEE Main · 2022 · 29 Jun 2022 · Shift 2 · Single correct option
