when a point charge is suspended at point of suspension of a pendulam given same charge ,what is the time period of pendulum

Dear Madhu

only presence of charge will not effect the time period

if there is electric field then it will affect the time period.

suppose a electric field E is acting vertically upword direction

then mg-qE is the resultant force in verticle direction

net acceleration g'=g-qE/m

Time period T=2∏√l/g'

                   =2∏√{l/(g-qE/m)}