21.2 Electromotive Force: Terminal Voltage

Calculate the internal resistance of a voltage source if the terminal voltage of the source increases by 1 V when the current supplied decreases by 4 A? Suppose this source is connected in series (in the same direction) to another source with a different voltage but same internal resistance. What will be the total internal resistance? How will the total internal resistance change if the sources ar…

Standard automobile batteries have six lead-acid cells in series, creating a total emf of 12.0 V. What is the emf of an individual lead-acid cell?

What is the output voltage of a 3.0000-V lithium cell in a digital wristwatch that draws 0.300 mA, if the cell’s internal resistance is $2 . \text{00} \Omega$?

What is the internal resistance of an automobile battery that has an emf of 12.0 V and a terminal voltage of 15.0 V while a current of 8.00 A is charging it?

The hot resistance of a flashlight bulb is $2 . \text{30} \Omega$, and it is run by a 1.58-V alkaline cell having a $0 . \text{100}-\Omega$ internal resistance. (a) What current flows? (b) Calculate the power supplied to the bulb using $I^{2} R_{\text{bulb}}$. (c) Is this power the same as calculated using $\frac{V^{2}}{R_{\text{bulb}}}$?

An automobile starter motor has an equivalent resistance of $0 . \text{0500} \Omega$ and is supplied by a 12.0-V battery with a $0 . \text{0100}-\Omega$ internal resistance. (a) What is the current to the motor? (b) What voltage is applied to it? (c) What power is supplied to the motor? (d) Repeat these calculations for when the battery connections are corroded and add $0 . \text{0900} \Omega$ to the circuit. (Significant problems are caused by even small amounts o…

(a) What is the internal resistance of a voltage source if its terminal voltage drops by 2.00 V when the current supplied increases by 5.00 A? (b) Can the emf of the voltage source be found with the information supplied?

A 1.58-V alkaline cell with a $0 . \text{200}-\Omega$ internal resistance is supplying 8.50 A to a load. (a) What is its terminal voltage? (b) What is the value of the load resistance? (c) What is unreasonable about these results? (d) Which assumptions are unreasonable or inconsistent?