A particle of charge 1 microcoulomb and mass 1 gm moving with velocity 4m/s is subjected to a uniform electric field of magnitude 300 V/m for 10 sec then its final speed cannot be:

A] 0.5 B] 4 C] 3 D] 6

Electrostatic force on the charge particle will be

Now there are two possibility.

1)electric field is in the direction of velocity 

case 2. if electric field is in opposite direction of velocity

So its final speed can be between 1m/s to 7m/s depending

on the angle between electric field and velocity vector

So, option 0.5 m/s is not possible in 10 sec interval

Hence option (1) is correct