Final answer:
The action potential will be the same in strength, speed, and duration.
Step-by-step explanation:
The action potential is an all-or-none event, meaning that it either occurs or it doesn't. Therefore, if the magnitude of the incoming electrical signal is doubled, the action potential will still be the same in strength, speed, and duration. This is because once the threshold for the action potential is reached, the same event occurs regardless of the strength of the stimulus.