fundamentally, sources of energy). The emf of a battery can be calculated using the definition mentioned above: E = W /q. The units of emf are joules per coulomb, that is, volts. OB The terminals of a battery are often labeled + and - for "higher potential" and "lower potential," respectively. The OC potential difference between the terminals is called the terminal voltage of the battery. If no current is running OD through a battery, the terminal voltage is equal to the emf of the battery: A Vbat = &. However, if there is a current in the circuit, the terminal Submit Previous Answers voltage is less than the emf because the battery has its own internal resistance (usually labeled r). When charge q passes through the battery, the battery does the Correct amount of work &q on the charge; however, the charge In diagrams A and B, the voltmeter readings would actually be also "loses" the amount of energy equal to Ir ( I is the connect the voltmeter in order to measure the terminal voltage. current through the circuit); therefore, the increase in potential energy is Eq - qir, and the terminal voltage is AVbat = E - Ir. Part F In order to answer the questions that follow, you should first review the meaning of the symbols describing various elements of the circuit, including the ammeter In which diagram does the voltmeter read almost zero? and the voltmeter; you should also know the way the ammeter and the voltmeter must be connected to the rest Select the letter(s) corresponding to the correct diagram(s). of the circuit in order to function properly Note that the internal resistance is usually indicated as a A separate resistor drawn next to the "battery" symbol. It is important to keep in mind that this resistor with B resistance r is actually inside the battery. mc In all diagrams, & stands for emf, r for the internal resistance of the battery, and R for the resistance of the V D external circuit. As usual, we'll assume that the connecting wires have negligible resistance. We will also assume that both the ammeter and the voltmeter are Previous Answers ideal: That is, the ammeter has negligible resistance, and the voltmeter has a very large resistance. Correct The voltmeter in diagram D is connected to two points that are energy, and the potential difference (voltage) is nearly zero. Part G Figure In which diagram or diagrams does the ammeter read almost zero? Select the letter(s) corresponding to the correct diagram(s). B O A R O B OC OD D Submit Request Answer Part H Complete previous part(s)