Exam 27: Circuits

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.

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:

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:

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:

The positive terminals of two batteries with emf's of ε₁ and ε₂, respectively, are connected together.Here ε₁ > ε_2. The circuit is completed by connecting the negative terminals.If each battery has an internal resistance of r, the rate in watts at which electrical energy is converted to chemical energy in the smaller battery is:

A battery of emf 24 V is connected to a 6- $\Omega$ resistor.As a result, current of 3 A exists in the resistor.The terminal potential difference of the battery is:

To make a galvanometer into an ammeter, connect:

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 current in the 4- $\Omega$ resistor is:

"The sum of the emf's and potential differences around a closed loop equals zero" is a consequence of:

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 current in each battery is:

In the figure, voltmeter V₁ reads 600 V, voltmeter V₂ reads 580 V, and ammeter A reads 100 A.The power wasted in the transmission line connecting the power house to the consumer is:

Each of the resistors in the diagram is 12 $\Omega$ .The resistance of the entire circuit 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 be dimmest?

The current in the 5.0- $\Omega$ resistor in the circuit shown is:

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

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 current in the 3- $\Omega$ resistor is:

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

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

A charged capacitor is being discharged through a resistor.At the end of one time constant the charge has been reduced by (1 - 1/e)= 63% of its initial value.At the end of two time constants the charge has been reduced by what percent of its initial value?

An ideal battery has an emf of 12 V.If it is connected to a circuit and creates a current of 4.0 A, what is the power?