Answer:
 3.6V
Step-by-step explanation:
Given parameters: 
Current = 0.012A
Resistance = 300Ω
Unknown: 
Voltage = ? 
Solution: 
According to ohm's law, voltage in a circuit is expressed mathematically as shown below: 
 Voltage = Current x Resistance 
 Insert the given parameters and solve; 
 Voltage = 0.012 x 300 = 3.6V