Flashlight Bulb Power and Battery Terminal Voltage

Step 1 of 3
Given: 
The battery voltage, \(\mathrm{V}=3 \mathrm{~V}\) 
The bulb resistance, \(R=6 \Omega\) 
The internal resistance of the battery, \(r=1 \Omega\)
We can start by calculating the total resistance in the circuit, which is just the sum of the internal resistance of the battery and the resistance of the bulb:
\(\mathrm{R}_{\text {otal }}=\mathrm{R}+\mathrm{r}=6 \Omega+1 \Omega=7 \Omega\)