Consider the intersection of the given cone
with a sphere of radius R The solid angle DW of the cone is defined to be equal
to DS/R
2, where DS is the area on the sphere cut out by the cone Rationalised 2023-24
Electric Charges
and Fields
21
a curve drawn in such a way that the tangent to it at each
point is in the direction of the net field at that point An
arrow on the curve is obviously necessary to specify the
direction of electric field from the two possible directions
indicated by a tangent to the curve