Question

What will be the resultant magnetic field at origin due to four infinite length wires. If each wire produces magnetic field 'B' at origin

• A. 4 B
• B.
• C.
• D. Zero

Answer 1

Answer: (C)

Answer 2

Direction of magnetic field (B₁, B₂, B₃ and B₄) at origin due to wires 1, 2, 3 and 4 are shown in the following figure.

$B _ { 1 } = B _ { 2 } = B _ { 3 } = B _ { 4 } = \frac { \mu _ { 0 } } { 4 \pi } \cdot \frac { 2 i } { x } = B$ . So net magnetic field at origin O

$= \sqrt { ( 2 B ) ^ { 2 } + ( 2 B ) ^ { 2 } } = 2 \sqrt { 2 } B$