# What is the total effective resistance of the two resistors? A 12.4-ohm resistor, R1, and a 30.-ohm resistor, R2, are to be connected in parallel between points A and B in a circuit containing a...

What is the total effective resistance of the two resistors?

A 12.4-ohm resistor, R1, and a 30.-ohm resistor, R2, are to be connected in parallel between points A and B in a circuit containing a 90.-volt battery.

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Expert Answers

ndnordic | Certified Educator

For resistors in parallel, the effective resistance will always be less than the lowest individual resistor in the circuit.

To find the effective resistance (Re) use the following formula:

1/Re = 1/R1 + 1/R2 + ...

In your example:

1/Re = 1/12.4 + 1/30

solving for Re = 8.77 ohms.

Just remember to take the inverse of your answer on the left to get the value of Re!