Which circuit has the largest equivalent resistance?

A. B. C. D.
circuit with 2 10-ohm resistors in series
Incorrect. This circuit has a total resistance of 20 Ohms which is not the largest of the four. 		circuit with 2 10-ohm resistors in parallel
Incorrect. This circuit has a total resistance of 5 Ohms which is not the largest of the four. 		circuit with 3 10-ohm resistors in series
Correct! This circuit has a total resistance of 30 Ohms which is the largest of the four choices. 		circuit with 3 10-ohm resistors in parallel
Incorrect. This circuit has a total resistance of 3.33 Ohms which is the smallest of the four.

Two 100 Ω resistors are connected in series to a 240 V voltage source. What is the equivalent resistance of this series circuit?

  1. 440 Ω
    Incorrect. You should only add the resistors together, not the resistors and the voltage.
  2. 200 Ω
    Correct! Series resistors are added directly.
  3. 50 Ω
    Incorrect. You added the resistors in parallel.
  4. 41.4 Ω
    Incorrect. You added the resistors and the voltage together in parallel.

Three resistors, 100 Ω, 150 Ω, and 240 Ω, are connected in parallel to a 120 V voltage source. What is the equivalent resistance of this parallel circuit?

  1. 48 Ω
    Correct! You added the reciprocals of the resistor values and then took the reciprocal of the result.
  2. 34.3 Ω
    Incorrect. You added the resistors and the voltage source in parallel.
  3. 0.0208 Ω
    Incorrect. You added the reciprocals of the resistor values, but forgot to take the reciprocal of the result.
  4. 390 Ω
    Incorrect. You added the resistors in series.

Determine the equivalent resistance for the circuit shown.

series circuit with three resistors: 150 ohms, 100 ohms, and 82 ohms

  1. 26.9 Ω
    Incorrect. This would be the total if you added the resistors and battery together in parallel.
  2. 452 Ω
    Incorrect. You added the resistors and the battery together.
  3. 34.65 Ω
    Incorrect. This would be the value if the resistors were added in parallel.
  4. 332 Ω
    Correct! The total resistance is the sum of the individual resistor values.

Determine the equivalent resistance for the circuit shown.

parallel circuit with three resistors: 100 ohms, 270 ohms, and 330 ohms

  1. 0.017 Ω
    Incorrect. You added the reciprocals of the resistor values, but forgot to take the reciprocal of the result.
  2. 39.9 Ω
    Incorrect. You added the resistors and the battery in parallel.
  3. 59.76 Ω
    Correct! You correctly added the reciprocals of the resistor values and took the reciprocal of the result.
  4. 700 Ω
    Incorrect. This would be the total if the resistors were in series.