A current of 10A flows through a semicircular wire of radius 2 cm as shown in figure (a). What is direction and magnitude of the magnetic field at the centre of semicircle? Would your answer change if the wire were bent as shown in figure (b) ?

Explanation

(i) `B = (10^(-7) xx pi xx 10)/(2xx10^(-2))= 5pi xx 10^(-5)` T (inwards).
(ii) `B= 5p xx 10^(-5)` T (inwards).