An electric field is acting vertically upwards. A small body of mass 1 gm and charge  -1μC  is projected with a velocity 10 m/s at an angle 450 with horizontal. Its horizontal range is 2m then the intensity of electric field is : (g = 10 m/s2)

As charge is negative and the electric field is vertically upwards the total force acting on the charge is vertically downwards.  Hence the net acceleration downwards is g+qEmR=V2sin2θg+qEm=V2g+qEmθ=45oR=10010+10−6E10−3=10+10−3E=50E=40×103  N/C