To solve this problem we will use the concepts related to Ohm's law for which voltage, intensity and resistance are related.
Mathematically this relationship is given as
[tex]V = IR \rightarrow R= \frac{V}{I}[/tex]
Where,
V= Voltage
I = Current
R = Resistance
The value of the given voltage is 12V, while the current is 12mA, therefore the resistance would be
[tex]R = \frac{12}{12*10^{-3}}[/tex]
[tex]R = 1000 \Omega[/tex]
Therefore the resistance is [tex]1000\Omega[/tex]