An electron with kinetic energy K _ 1 enters between parallel plates of a capacitor at an angle α with the plates. It leaves the plates at angle β with kinetic energy K _ 2 . Then the ratio of kinetic energies K _ 1 : K

Correct answer: D. ^ 2 β ^ 2 α velocity along the plate will not change. ∴ v _ 1 cosα = v _ 2 cosβ K _ 1 K _ 2 ⇒ v _ 1 ^ 2 v _ 2 ^ 2 = ^ 2 β ^ 2 α

JEE Main 202125 FebruaryEvening Shift

JEE Main 2021 · 25 February · Evening Shift · Physics · Magnetic Effects of Current

An electron with kinetic energy K _ 1 enters between parallel...

An electron with kinetic energy

{K}_{1}

enters between parallel plates of a capacitor at an angle

\alpha

with the plates. It leaves the plates at angle

\beta

with kinetic energy

{K}_{2} .

Then the ratio of kinetic energies

{K}_{1}: {K}_{2}

will be :

D. $\dfrac{\cos^{2}\beta}{\cos^{2}\alpha}$

An electron with kinetic energy K _ 1 enters between parallel plates of a capacitor at an angle α with the plates. It

velocity along the plate will not change.

$∴ {v}_{1}cos\alpha = {v}_{2}cos\beta$

$\dfrac{{K}_{1}}{{K}_{2}} ⇒ {v}_{1}^{2}{v}_{2}^{2} = \dfrac{\cos^{2}\beta}{\cos^{2}\alpha}$