a thin circular wire of radius r has a charge Q. if a point charge q is placed at the centre of the ring, then find the increase in tension in the wire.

At the point when the charge q=+Q is given to the wire then it comes in pressure which is called circle strain. At the point when at the focal point of the ring another charge q0=+Q'is given, the pressure in the wire increments to keep this fragment into equillibrium once more. 

Presently we can consider the basic strip subtended at an edge Ѳ at its inside. 

As the string is in balance in x bearing. For harmony in y course. 

F = 2T sin(dѳ/2)......................... (1.) 

q/2π xdѳ 

Charge on the strip 

F = 1/4 πɛ x q/2π x(dѳ xqo)/r2 - - (2.) 

Subsitute 2 of every 1 

2T dѳ/2 =1/4 πɛ x q/2π x(dѳ xqo)/r2 

T = qq0/8π2ɛr2.