A helium ion of mass 4m and charge 2e is accelerated from rest through a potential difference V in vacuum. Its final speed will be

Explanation:

The helium ion has:

a potential difference in vacuum = V,

Charge = 2e

and mass = 4m,

speed = v,

mass = 4m

From electrostatics, the work done is the product of charge and its potential difference.

Therefore, Work done = charge × potential difference = 2e × V = 2eV

This work done is in form of kinetic energy, therefore:

Kinetic energy = 1/2 × mass × speed²

⇒  Work done = Kinetic energy

when it gains or loses electrons

distance = 150m

displ = root (50 ^2 + 100^2)

root(2500+10000)

root 125000