A particle of mass m and charge q is fastened to one end of a string of length l . The other end of the string is fixed to the point O. The whole system lies on a frictionless horizontal plane. Initially, the mass is at rest at A . A uniform electric field in the direction shown is then switched on. Then
(a) the speed of the particle when it reaches B is √2qEl/m
(b) the speed of the particle when it reaches B is √qEl/m
(c) the tension in the string when particles reaches at B is qE
(d) the tension in the string when the particle reaches at B is 2qE
