In fig. what is the magnetic field induction at point o
μ0i4πr
μ0i4r+μ0i2πr
μ0i4r+μ0i4πr
μ0i4r−μ0i4πr
B at O will be due to the following portions :(i) vertical straight portion. This is zero.(ii) circular portion. This is given byBcircular =12μ0i2r=μ0i4r(iii) straight horizontal portion. This is given byBstraight =μ0i4πr∴ BTotal =μ0i4r+u0i4πr