Exam 27: Circuits

An initially uncharged capacitor C is connected in series with resistor R. This combination is then connected to a battery of emf V₀. Sufficient time elapses so that a steady state is reached. Which of the following statements is NOT true?

A certain galvanometer has a resistance of 100 $\Omega$ and requires 1 mA for full scale deflection. To make this into a voltmeter reading 1 V full scale, connect a resistance of:

Two wires are made of the same material and have the same length but different radii. They are joined end-to-end and a potential difference is maintained across the combination. Of the following the quantity that is the same for both wires is:

To make a galvanometer into an ammeter, connect:

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

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

A certain ammeter has an internal resistance of 1 $\Omega$ and a range from 0 to 50 mA. To make its range from 0 to 5 A, use:

The terminal potential difference of a battery is less than its emf:

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

A portion of a circuit is shown, with the values of the currents given for some branches. What is the direction and value of the current i?

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:

The positive terminals of two batteries with emf's of ₁ and ₂, respectively, are connected together. Here ₁ > _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 certain capacitor, in series with a 720- $\Omega$ resistor, is being charged. At the end of 10 ms its charge is half the final value. The capacitance is about:

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?

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

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:

Two wires made of the same material have the same length but different diameters. They are connected in series to a battery. The quantity that is the same for the wires is:

Two 110-V light bulbs, one labeled 25 W and the other 100 W, are connected in series to a 110 V source. Then:

By using only two resistors, R₁ and R₂ a student is able to obtain resistances of 3 $\Omega$ , 4 $\Omega$ , 12 $\Omega$ , and 16 $\Omega$ . The values of R₁ and R₂ are:

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: