The current in the circuit shown is 2.0 a. what is the value of r3? 10 ω 15 ω 20 ω 55 ωanswer was a

Ohm's law allows us to find the equivalent resistance of the circuit. In fact:

where
V is the voltage of the battery
I is the current in the circuit
is the equivalent resistance

Re-arranging the equation and using the data of the problem, we get


The three resistors are in series, so their equivalent resistance is just the sum of the three resistances:

Since we know the value of the equivalent resistance, , we can find the value of R3: