posted by culata on .
please,i need help on this question:a thin circular ring of radius 20cm is charged with a uniform charge density(rho),if a small section of 1cm length is removed from the ring.calculate the electric field intensity at the center of the ring
At the center of the ring, the charge would be zero at the center before the 1 cm segment is removed, due to symmetry considerations. Use a principle of superposition. The ring with a segment removed is the same as a complete ring (zero field) minus a 1 cm segment of the opposite charge. The latter can be approximated as the field of a point charge or, with better accuracy, as a straight line segment. You want the field 20 cm away, normal to the line.
Atthe centre of the ring the electric field is zero.because the ring is considered as a point,which cannot experience its own field except by an external body