Exam 27: Circuits

A 3- $\Omega$ and a 1.5- $\Omega$ resistor are wired in parallel and the combination is wired in series to a 4- $\Omega$ resistor and a 10-V emf device. The potential difference across the 3- $\Omega$ resistor is:

Resistor 1 has twice the resistance of resistor 2. The two are connected in parallel and a potential difference is maintained across the combination. The rate of thermal energy dissipation in 1 is:

In the diagrams, all light bulbs are identical and all emf devices are identical. In which circuit (I, II, III, IV, V) will the bulbs glow with the same brightness as in circuit X?

Four 20- $\Omega$ resistors are connected in parallel and the combination is connected to a 20-V emf device. The current in any one of the resistors is:

Two identical batteries, each with an emf of 18 V and an internal resistance of 1 $\Omega$ , are wired in parallel by connecting their positive terminals together and connecting their negative terminals together. The combination is then wired across a 4- $\Omega$ resistor. The potential difference across the 4- $\Omega$ resistor is:

Four wires meet at a junction. The first carries 4 A into the junction, the second carries 5 A out of the junction, and the third carries 2 A out of the junction. The fourth carries:

A battery has an emf of 9 V and an internal resistance of 2 $\Omega$ . If the potential difference across its terminals is greater than 9 V:

Four circuits have the form shown in the diagram. The capacitor is initially uncharged and the switch S is open. The values of the emf , resistance and R, and capacitance C for each for the circuits are Rank the circuits according to the current just after switch S is closed least to greatest.

"The sum of the currents into a junction equals the sum of the currents out of the junction" is a consequence of:

Resistor 1 has twice the resistance of resistor 2. The two are connected in series and a potential difference is maintained across the combination. The rate of thermal energy dissipation in 1 is:

A certain voltmeter has an internal resistance of 10,000 $\Omega$ and a range from 0 to 12 V. To extend its range to 120 V, use a series resistance of:

The circuit shown was wired for the purpose of measuring the resistance of the lamp L. Inspection shows that:

In the diagram, the current in the 3- $\Omega$ resistor is 4 A. The potential difference between points 1 and 2 is:

Four circuits have the form shown in the diagram. The capacitor is initially uncharged and the switch S is open. The values of the emf , resistance R, and the capacitance C for each of the circuits are Rank the circuits according to the time after switch S is closed for the capacitors to reach half their final charges, least to greatest.

A 120-V power line is protected by a 15-A fuse. What is the maximum number of 120 V, 500 W light bulbs that can be operated at full brightness from this line?

In the capacitor discharge formula q = q₀e^-t/RC the symbol t represents:

A series circuit consists of a battery with internal resistance r and an external resistor R. If these two resistances are equal (r = R) then the energy dissipated per unit time by the internal resistance r is:

Nine identical wires, each of diameter d and length L, are connected in series. The combination has the same resistance as a single similar wire of length L but whose diameter is:

The resistance of resistor 1 is twice the resistance of resistor 2. The two are connected in parallel and a potential difference is maintained across the combination. Then:

The equivalent resistance between points 1 and 2 of the circuit shown is: