Final answer:
When a person touches a 120 V AC source and is standing on a rubber mat with a resistance of 350 kOhm, the current through her would be 0.343 mA, which is below the threshold for involuntary muscle contraction.
Step-by-step explanation:
When a person touches a 120 V AC source and is standing on a rubber mat with a resistance of 350 kΩ, we can find the current by using Ohm's Law: I = V/R, where I is the current, V is the voltage, and R is the resistance. In this case, the current would be:
I = 120 V / 350 kΩ = 0.343 mA (rounded to three decimal places)
This current is below the threshold of 10 mA, so it would not lead to involuntary muscle contraction. Therefore, if she touches the 120 V AC source while standing on a rubber mat with a resistance of 350 kΩ, there would be no significant effect on her.