Answer:
V=4v
Step-by-step explanation:
To perform this operation, we will refer to Ohm's Law. This Law relates the terms current, voltage and resistance.
The current intensity that passes through a circuit is directly proportional to the voltage or voltage of the circuit and inversely proportional to the resistance it presents.

Where
I=Current
V= Voltage
R=Resistance.
So, in this case:
R=200 ohm
I= 2mA = 0.002 A
V= searched variable

