Science whizzes! Were you able to solve our ACT Science challenge question this week? If you need a refresher, check out the question and passage here, and then truck on down below for the answer and explanation.

## ACT Challenge Question 20

The total resistance in a circuit for resistors connected in series is the sum of their individual resistances. Suppose the student rewired the circuit with a 3.0 ohm and a 6.0 ohm resistor in series, using a 3.0 V battery to supply the voltage. What current would an ammeter placed in this circuit most likely read?

A. 0.333 amps

B. 0.667 amps

C. 1.333 amps

D. 1.500 amps

## Answer and Explanation

The correct answer is** A**.

Applying the definition in the question, we can see that the resistance for a circuit with a total resistance of 3.0 + 6.0 = 9.0 ohms will be the same as it is for a 9.0 ohm resistor alone. Going back to Table 2, we can look up this value as 0.327 amps. Answer choice A is closest to this number. Alternately, you could calculate the current using the formula provided to come up with the exact value. Note that answer choice C is a trap for students who make a bad assumption by simply adding up the measured currents listed in the table for resistors of 3.0 and 6.0 amps.