How Does a Potential Difference Affect Kinetic Energy of a Charged Particle?

[pat666]

Homework Statement

A particle with charge -3e is accelerated from rest through a potential difference of 200v .
This gives the particle a kinetic energy of?

Homework Equations

The Attempt at a Solution

what does a charge of -3e mean?(-3*2.71...?) to kind the KE wouldn't i need a mass too??

 

[Fightfish]

e = charge of an electron.
Try using conservation of energy?

 

[pat666]

ok so the P.d = Ke??
I can't see that - can you give me a bit more please.

 

[Onamor]

when a charged particle passes through a PotDif it "gains energy." (from the fields) since this is a particle of (assumed) no internal structure, the energy it gains will be in kinetic, not potential. Therefore you don't need a mass, the question just wants the energy.

the equation you need is indeed E = q.V (where q is the charge on the particle)

to better understand this, remember that we assume the particle does not "see" the potential when it is at an infinite distance from it (potential **difference** from that at infinity).
So in essence, the value of KinEn is how much the potential "wants" the particle to pass through it.

 

[pat666]

thanks Onamor - problem solved