Question

two long parallel wires at distance d apart carry current 1A and 3A in opposite direction. the wire carrying 1A current lies to the left of the wire. the points at which their magnetic field cancel are located at
a. a distance of d/4 to the right of the first wire
b. a distance of d/2 to the left of the first wire
c. a distance of d/4 to the right of the second wire
d. a distance of d/2 to the right of the second wire
( plz answer with explanation )

Answer 1

Answer:

b. d/2 to the left of the first wire

Answer 2

C is the correct option.

Allow the magnetic field at point P to be zero. This is the correct option.

Due to wire 1, the permanent magnet at location P is B 1 = 2(0.08x) o I 1

​

The Magnetic field at point P owing to wire 2, B 2 = 2(x) o I 2 into the plane of the paper Magnetic field at point P due to wire 2, B 2 = 2(x) o I 2

​ 2(0.08x) o I 1 o I 1 o I 1 o I 1 o I 1 o I 1 o I 1 o I 1 o I 1 o I 1 o I 1

​ = 2x o I 2 x o I 2 x o I 2 x o I 2 x o

Alternatively, 0.08x I 1

= x I 2 x I 2 x I 2 x I 2 x

x 5 + 0.08x 3 = x 5

​ x=0.05 m x=0.05 m x=0.05 m x=0.05