Formula for electric potential energy

[darksyesider]

In a velocity selector apparatus, i had an electric potential set across two points, and a proton at rest at one end. The potential was 350 V.

My instructor used :

qV = 1/2 mv^2 to find the velocity at the end of the apparatus.

Where did the left hand side of the eqn come from??

 

[Doc Al]

qV = 1/2 mv^2 to find the velocity at the end of the apparatus.

Where did the left hand side of the eqn come from??

That describes the energy gained by a charge q moving through a potential difference V. (The work done by the field on the charge.)

 

[Doc Al]

You may want to review this: Work done by electric field

 

[Vb123]

qv=(0.5)mv^2
This expression indicates Kinetic Energy gained by a body with charge q while moving in a region of Electric potential v.