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# Stopping Potential watch

1. We know that
eVs (stopping potential in electron volts) = KE of electron

Does this apply to ANY potential difference, thereby saying that
eV = KE of electron
2. (Original post by jsmith6131)
We know that
eVs (stopping potential in electron volts) = KE of electron.

Does this apply to ANY potential difference, thereby saying that
eV = KE of electron
Not precisely.

If is potential difference, then the work done on a particle by electric field is . This results in change of kinetic energy of a particle.

Stopping potential difference for an electron is such a potential difference that will make the electron loose all its kinetic energy. So in this special case when the final kinetic energy is 0, you can say that .

However, depending on the values (and signs) of potential difference and the charge of a particle, electric field may cause it to loose or gain kinetic energy.
In a general case though the movement in an electric field results in a change of kinetic energy.
Spoiler:
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If you want to express it by an equation:

in any conservative field (such as electric or gravitational field) the change in potential energy and change in kinetic energy give a sum of 0: (conservation of energy).
3. ok, so
qV = -KE
where q = charge on an electron

So basically if an electron was in a potential different of say 10 kV then the velocity of the electron would be
about 5.93 * 10^7 m/s
4. (Original post by jsmith6131)
ok, so
qV = -KE
where q = charge on an electron

So basically if an electron was in a potential different of say 10 kV then the velocity of the electron would be
about 5.93 * 10^7 m/s
If the electron has moved through a potential difference of +10kV and its initial velocity was 0, then , and yes, it would gain velocity around .

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