Question

A 12 v battery is connected across two parallel metal plates separated by 0.30 cm. find the magnitude of the electric field.

Answer 1

The electric field between two parallel metal plates is given by
$E= \frac{V}{d}$
where
E is the electric field
V is the voltage across the two plates
d is the separation between the two plates.

In our problem, the voltage is $V=12 V$ while the separation between the plates is $d=0.30 cm=0.003 m$, therefore the magnitude of the electric field is
$E= \frac{V}{d}= \frac{12 V}{0.003 m}=4000 V/m$