A long straight wire carrying electric current ' i ' is bent at its mid point to form an angle of 45 ° as shown in the figure. Magnetic field at a point P at a distance d from the point Q of bending is

Step-by-step solution

Recall the formula of the magnetic field due to finite straight wire, B = μ 0 i 4 π r sin ϕ 1 + sin ϕ 2 here r = d cos 45 ° ,   ϕ 1 = 90 °   &   ϕ 1 = - 45 ° B = μ 0 i 4 π d cos 45 ° sin 90 ° + sin - 45 ° B = μ 0 i 4 π d cos 45 ° sin 90 ° + sin - 45 ° B = μ 0 i 2 4 π d 1 - 1 2 B = μ 0 i 4 π d 2 - 1