Question

The tracks of three charged particles in a uniform electrostatic field as shown in the figure. Which particle has the highest charge to mass ratio?

• A. $A$
• B. $B$
• C. $C$
• D. $A$ and $B$

Answer 1

Answer: (C)

$C$

Particles $A$ and $B$ have negative charges because they are being deflected towards the positive plate of the electrostatic field. Particle $C$ has positive charge because it is being deflected towards the negative plate.

$\therefore$ Deflection of charged particle in time $t$ in $y$-direction

$h\times t+\frac{1}{2}a{t}^2=\frac{1}{2}\frac{qE}{m}{t}^2$

i.e., $h\propto q/m$

As the particle $C$ suffers maximum deflecton in y-direction, so it has heighest charge to mass $q/m$ ratio.