Final answer:
Using Ohm's law, the current through a person touching a 120-V AC source while standing on a rubber mat with 300 kΩ resistance is calculated to be 0.40 mA, which generally has no harmful effect. Therefore the correct answer is a) 0.40 mA, No harmful effect.
Step-by-step explanation:
To find the current through a person touching a 120-V AC source while standing on a rubber mat with a total resistance of 300 kΩ, Ohm's law is used, which states I = V/R (where I is current, V is voltage, and R is resistance).
Using this relationship, current I = 120 V / 300,000 Ω = 0.0004 A, or 0.40 mA. This current is typically not harmful to humans. Considering the resistance values and their effects on the body, the correct option would be (a) 0.40 mA, No harmful effect.
The current through a person can be found using Ohm's Law, which states that I = V/R, where I is the current, V is the voltage, and R is the resistance. In this case, the voltage is 120 V AC and the resistance is 300 kΩ (or 300,000 Ω).
Plugging these values into the formula, we get I = 120 V / 300,000 Ω = 0.4 mA. Therefore, the current through the person is 0.4 mA.
If the person is standing on a rubber mat, which provides insulation, the effect on her would be no harmful effect as the current is very low and does not pose a danger to her.