Q.

A very long conducting wire is bent in a semi-circular shape from A to B as shown in figure. The magnetic field at point P for steady current configuration is given by   [2023]


 

1 μ0i4R[1-2π] pointed away from page  
2 μ0i4R[1-2π] pointed into the page  
3 μ0i4R pointed into the page  
4 μ0i4R pointed away from the page  

Ans.

(1)

Bp due to wire 1=μ0i4πR 

Bp due to wire 3=μ0i4πR 

Bp due to wire 2=μ0i4R 

Bnet=-μ0i2πR+μ0i4R=μ0i4R[-2π+1]=μ0i4R[1-2π]

Pointed away from page.