Chapter 1, Problem 1.27P

Figure P1.27 shows an ammeter (AM) and voltmeter (VM) connected to measure the current and voltage, respectively, for circuit element A.When current actually enters the + terminal of the ammeter, the reading is positive, and when current leaves the + terminal, the reading is negative. If the actual voltage polarity is positive at the + terminal of the VM, the reading is positive; otherwise, it is negative. (Actually, for the connection shown, the ammeter reads the sum of the current in element A and the very small current taken by the voltmeter. For purposes of this problem, assume that the current taken by the voltmeter is negligible.) Find the power for element A and state whether energy is being delivered to element A or taken from it if

Figure P1.27

1. the ammeter reading is +2 A and the voltmeter reading is +30 V;

the ammeter reading is -2 A and the voltmeter reading is -30 V.

the ammeter reading is -2 A and the voltmeter reading is +30 V;