A particle of mass m and charge q is thrown at a speed u against a uniform electric field E. How much distance will it travel before coming to momentary rest?

Explanation

Given U=velocity of projection
` E=electric field intensity `
` Q=charge, `
` m=mass of particle `
We know, force experience by a particle with charge e in an electric `field=qe `
` acceleration produced=(qe)/m `
As the particle is projected against the electric field, Hence `deceleration=(qe) /m `
So, Let the distance covered be s
` Then v^2=U^2+2as [where a =acceleration, v=final velocity] `
` here 0=u^2-2axxs `
` rArr s=u^2/(2a)=(m u^2)/(2qe)`