Exam 27: Circuits

In the circuit shown, both resistors have the same value R.Suppose switch S is initially closed and capacitor C is charged.When switch S is then opened, the circuit has a time constant _a.Conversely, suppose S is initially open and capacitor C is uncharged.When switch S is then closed, the circuit has a time constant 11ef00bf_7880_91f1_bc85_1792c21a71f3_TB6585_11 _b.The ratio 11ef00bf_7880_91f1_bc85_1792c21a71f3_TB6585_11 _a/ 11ef00bf_7880_91f1_bc85_1792c21a71f3_TB6585_11 _b is:

Suppose the current charging a capacitor is kept constant.Which graph below correctly gives the potential difference V across the capacitor as a function of time?

_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 voltmeter has an internal resistance of 10,000 $\Omega$ and a range from 0 to 100 V.To give it a range from 0 to 1000 V, one should 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 parallel and the combination is connected to a 20-V emf device.The current in any one of the resistors is:

Resistor 1 has twice the resistance of resistor 2.They are connected in parallel to a battery.The ratio of the thermal energy dissipation by 1 to that by 2 is:

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:

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 time constant RC has units of:

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:

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:

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

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:

If a circuit has L closed loops, B branches, and J junctions the number of independent loop equations is: