I.E. Irodov
Problems in General Physics, 1981
PROBLEM
3.223.	Find the magnetic induction of the field at the point О of a loop with current I, whose shape is illustrated
(a)	in Fig. 3.60a, the radii a and b, as well as the angle <p are known;
(b)	in Fig. 3.60fe, the radius a and the side b are known.
SOLUTION
3.223 (a) From the Biot-Savart law,
dB
Ho . (dl x 4л.1
So, magnetic field induction due to the segment 1 at O,
Ho i Зл _ Ho i . .co Ho i . .co _ --------— + 0 +--------— sin 45 +	— sin 45 +0 4л a 2 4ло	4ло
2
2a ' b
Ho . 3л
= 4л 1