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Uniform electric fields

Uniform electric fields

Uniform electric fields are fields where the electric field strength is constant in magnitude regardless of position within the field.

The field between two charged, parallel plates is a uniform electric field.

The electric field strength between these plates is given by: $$E=\frac{V}{d}$$ $E$ is the electric field strength, $V$ is the potential difference between the two plates and $d$ is the distance that separates the two plates.

The unit of electric field strength can be written as $\text{V m}^{-1}$, which is equivalent to $\text{N C}^{-1}$.

The direction of this field is from the plate with the higher potential to the plate with the lower potential.

Effects on moving charged particles

A charged particle moving through a uniform electric field will be deflected in a direction parallel to the field.

Whether the charge is deflected in the same or opposite direction of the field depends on the sign of the charge.

Proton deflection by a uniform electric field

The deflection downwards towards the negatively charged plate is caused by a force on the positively charged proton by the uniform electric field (recall that $F=qE$).

The same experiment involving an electron would result in an upward deflection.