According to Ohm's Law, how does current change if voltage is doubled at constant temperature?

According to Ohm’s Law (V = IR), if the voltage is doubled while temperature (and thus resistance) remains constant, the current also doubles.

This is because current is directly proportional to voltage when resistance is unchanged.
Mathematically:
If V∝I, then increasing voltage leads to a proportional increase in current.

For example, if the voltage increases from 5V to 10V, the current will also increase to twice its original value, provided resistance stays the same.