Figure shows tracks of three charged particles in a uniform electrostatic field. Give the signs of the three charges. Which particle has the highest charge to mass ratio ?

Explanation

Here, electric field is vertically downward (from upper positively charged plate to negatively charged plate).
As per the statement, since `q_(1)` and `q_2` are deflected towards positive plate, they must be negatively charged particles. But `q_3` is deflected towards negative plate and so it must be positively charged.
Here, if all the three particles enter uniform electric field E, perpendicularly with same horizontal constant velocity then vertical displacement undergone by them while coming out of electric field is,
`d =v_(0)t + 1/2 at^(2)`
`therefore y =(0)t + 1/2 (F_(e)/m) (1/v)^(2)`
`(therefore v_(0) = 0, v=1/t " and " F_(e) = ma)`
`therefore y=1/2 (qE)/(m) (l/v)^(2), (therefore F_( e) = qE)`
`therefore y prop q/m` (`therefore` E, I, v are same for all the three charges) `q_3` must have maximum specific charge (which is charge to mass ratio or charge per unit mass) because it undergoes maximum vertical displacement as shown in the figure 3.),