Answer:
The current halves
Step-by-step explanation:
The relationship between voltage, current and resistance in a circuit is given by Ohm's law:

where
V is the voltage
R is the resistance
I is the current
We can rewrite the formula as

we see that I is directly proportional to V and inversely proportional to R. In this problem, V is held constant while R is doubled:

so, the new current in the circuit will be

So, the current halves.