A stream of a positively charged particles having (q)/(m) = 2 × 10...

Acceleration of the particles due to electric field, $a = \dfrac{F}{m} = \dfrac{qE}{m} = \left(2 \times {10}^{11}\right)\left(1 . 8 \times {10}^{3}\right)$

$= 3 . 6 \times {10}^{14}m{s}^{- 2}$

Time to cross plates $= \dfrac{d}{v}$

$⇒ t = \dfrac{0 . 10}{3 \times {10}^{7}}$

Now deflection,

$y = \dfrac{1}{2}{at}^{2} = \dfrac{1}{2}\left(3 . 6 \times {10}^{14}\right){\left(\dfrac{0 . 10}{3 \times {10}^{7}}\right)}^{2}$

$= 0 . 002m$

$= 2mm$