This object shows two resistors in parallel and their combined resistance. Use the use the red sliders to change the resistance from 1Ω to 100Ω.

Notice what happens to the total resistance as one or both of the individual resistors is changed.

1. What is the combined resistance of two equal resistors in parallel?
2. Change one resistor to 1Ω. Notice what happens to the total resistance when the other resistor is changed? Why is that the case?
3. What is the rule that links the total resistance to the two resistance when in parallel?