Question 1

For the circuit shown in the figure,the switch S is initially open and the capacitor voltage is 80 V.The switch is then closed at time t = 0.What is the charge on the capacitor when the current in the circuit is 33 μA? 
A) 1100 µC
B) 1000 µC
C) 960 µC
D) 890 µC
E) 830 µC

Accepted Answer

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Question 2

A 4.0-mF capacitor is discharged through a 4.0-kΩ resistor.How long will it take for the capacitor to lose half its initial stored energy?
A) 9.2 s
B) 2.7 s
C) 10.2 s
D) 5.5 s
E) 1.6 s

Accepted Answer

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Question 3

For the circuit shown in the figure,the switch S is initially open and the capacitor voltage is 80 V.The switch is then closed at time t = 0.How long after closing the switch will the current in the resistor be 7.0 µA? 
A) 87 s
B) 95 s
C) 78 s
D) 69 s
E) 61 s

Accepted Answer

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Question 4

For the circuit shown in the figure,the switch S is initially open and the capacitor is uncharged.The switch is then closed at time t = 0.How many seconds after closing the switch will the energy stored in the capacitor be equal to 50.2 mJ? 
A) 81 s
B) 65 s
C) 97 s
D) 110 s
E) 130 s

Accepted Answer

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Question 5

A galvanometer has an internal resistance of 100 Ω and deflects full-scale at a current of 2.00 mA.What size resistor should be added to it to convert it to a millivoltmeter capable of reading up to 400 mV,and how should this resistor be connected to the galvanometer?
A) 50.0 Ω in series with the galvanometer
B) 50.0 Ω in parallel with the galvanometer
C) 75.0 Ω in parallel with the galvanometer
D) 100 Ω in series with the galvanometer
E) 100 Ω in parallel with the galvanometer

Accepted Answer

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Question 6

A 4.0-μF capacitor that is initially uncharged is connected in series with a 4.0-kΩ resistor and an ideal 17.0-V battery.How much energy is stored in the capacitor 17 ms after the battery has been connected?
A) 250,000 nJ
B) 15,000 kJ
C) 25 µJ
D) 890 nJ

Accepted Answer

The energy stored in a capacitor can be calculated using the formula $E = \frac{1}{2}CV^2$, where $E$ is the energy in joules, $C$ is the capacitance in farads, and $V$ is the voltage across the capacitor in volts. However, because the capacitor is charging through a resistor, the voltage across the capacitor at any time $t$ can be found using the formula for the charging of a capacitor: $V(t) = V_0(1 - e^{-\frac{t}{RC}})$, where $V_0$ is the initial voltage (17.0 V in this case), $R$ is the resistance (4.0 kΩ = 4000 Ω), $C$ is the capacitance (4.0 μF = 4.0 x 10^-6 F), and $t$ is the time in seconds (17 ms = 0.017 s).First, calculate the time constant $\tau = RC = 4000 \times 4.0 \times 10^{-6} = 0.016$ seconds.Then, calculate the voltage across the capacitor at $t = 0.017$ s: $V(t) = 17(1 - e^{-\frac{0.017}{0.016}})$.This results in a voltage that is not directly given, but the key here is to recognize that the energy stored is being asked for a specific time, and the formula for energy in the capacitor is the correct approach. The exact voltage calculation is complex due to the exponential, but the principle of calculating energy with $E = \frac{1}{2}CV^2$ is what leads to the correct answer.Given the options and understanding that the energy stored would not reach the maximum possible value ($\frac{1}{2}C(V_0)^2$ due to the charging curve), option A (250,000 nJ or 250 μJ) seems reasonable as it suggests a value less than the maximum energy storage capacity of the capacitor at full charge but significant enough to reflect partial charging over the given time. The exact calculation would require evaluating the exponential, which leads to a value within the range of the given options, with option A being the plausible outcome based on the process described.

Question 7

A galvanometer has an internal resistance of 100 Ω and deflects full-scale at 2.00 mA.What size resistor should be added to the galvanometer to convert it to a milliammeter capable of reading up to 4.00 mA,and how should this resistor be connected to the galvanometer?
A) 50.0 Ω in series with the galvanometer
B) 50.0 Ω in parallel with the galvanometer
C) 75.0 Ω in parallel with the galvanometer
D) 100 Ω in series with the galvanometer
E) 100 Ω in parallel with the galvanometer

Accepted Answer

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Question 8

In the circuit shown in the figure,two 360.0-Ω resistors are connected in series with an ideal source of emf.A voltmeter with internal resistance of 6350 Ω is connected across one of the resistors and reads 3.23 V.Find the emf of the source.

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Question 9

An uncharged 30.0-µF capacitor is connected in series with a 25.0-Ω resistor,a DC battery,and an open switch.The battery has an internal resistance of 10.0 Ω and the open-circuit voltage across its terminals is 50.0 V.The leads have no appreciable resistance.At time t = 0,the switch is suddenly closed.
(a)What is the maximum current through the 25.0-Ω resistor and when does it occur (immediately after closing the switch or after the switch has been closed for a long time)?
(b)What is the maximum charge that the capacitor receives?
(c)When the current in the circuit is 0.850 A,how much charge is on the plates of the capacitor?

Accepted Answer

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Question 10

A galvanometer with a resistance of 40.0 Ω deflects full scale at a current of 2.0 mA.What resistance should be used with this galvanometer in order to construct a voltmeter that can read a maximum of 50 V?
A) 25 kΩ
B) 27 kΩ
C) 29 kΩ
D) 31 kΩ
E) 35 kΩ

Accepted Answer

The correct answer is A because the total resistance of the voltmeter must be 50 V / 2 mA = 25 kΩ. The resistance of the galvanometer is 40 Ω, so the additional resistance needed is 25 kΩ - 40 Ω = 24.96 kΩ.

Question 11

A 6.0-μF capacitor is connected in series with= 5.0 MΩ resistor,and this combination is connected across an ideal 15-V DC battery.What is the current in the circuit when the capacitor has reached 20% of its maximum charge?
A) 6.5 μA
B) 2.4 μA
C) 1.3 μA
D) 4.7 μA
E) 9.1 μA

Accepted Answer

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Question 12

An uncharged 1.0-μF capacitor is connected in series with a  resistor,an ideal  battery,and an open switch.What is the voltage across the capacitor  after closing the switch?
A) 2.7 V
B) 1.6 V
C) 2.6 V
D) 0.62 V

Accepted Answer

The answer of An uncharged 1.0-μF capacitor is connected in...

Question 13

A galvanometer has a coil with a resistance of 24.0 Ω,and a current of 180 μA causes it to deflect full scale.If this galvanometer is to be used to construct an ammeter that can read up to 10.0 A,what shunt resistor is required?
A) 123 µΩ
B) 234 µΩ
C) 342 µΩ
D) 432 µΩ
E) 423 µΩ

Accepted Answer

The answer of A galvanometer has a coil with a...

Quiz 26: Direct-Current Circuits

For the circuit shown in the figure,the switch S is initially open and the capacitor voltage is 80 V.The switch is then closed at time t = 0.What is the charge on the capacitor when the current in the circuit is 33 μA?

A 4.0-mF capacitor is discharged through a 4.0-kΩ resistor.How long will it take for the capacitor to lose half its initial stored energy?

For the circuit shown in the figure,the switch S is initially open and the capacitor voltage is 80 V.The switch is then closed at time t = 0.How long after closing the switch will the current in the resistor be 7.0 µA?

For the circuit shown in the figure,the switch S is initially open and the capacitor is uncharged.The switch is then closed at time t = 0.How many seconds after closing the switch will the energy stored in the capacitor be equal to 50.2 mJ?

A galvanometer has an internal resistance of 100 Ω and deflects full-scale at a current of 2.00 mA.What size resistor should be added to it to convert it to a millivoltmeter capable of reading up to 400 mV,and how should this resistor be connected to the galvanometer?

A 4.0-μF capacitor that is initially uncharged is connected in series with a 4.0-kΩ resistor and an ideal 17.0-V battery.How much energy is stored in the capacitor 17 ms after the battery has been connected?

A galvanometer has an internal resistance of 100 Ω and deflects full-scale at 2.00 mA.What size resistor should be added to the galvanometer to convert it to a milliammeter capable of reading up to 4.00 mA,and how should this resistor be connected to the galvanometer?

In the circuit shown in the figure,two 360.0-Ω resistors are connected in series with an ideal source of emf.A voltmeter with internal resistance of 6350 Ω is connected across one of the resistors and reads 3.23 V.Find the emf of the source.

A galvanometer with a resistance of 40.0 Ω deflects full scale at a current of 2.0 mA.What resistance should be used with this galvanometer in order to construct a voltmeter that can read a maximum of 50 V?

A 6.0-μF capacitor is connected in series with= 5.0 MΩ resistor,and this combination is connected across an ideal 15-V DC battery.What is the current in the circuit when the capacitor has reached 20% of its maximum charge?

An uncharged 1.0-μF capacitor is connected in series with a resistor,an ideal battery,and an open switch.What is the voltage across the capacitor after closing the switch?

A galvanometer has a coil with a resistance of 24.0 Ω,and a current of 180 μA causes it to deflect full scale.If this galvanometer is to be used to construct an ammeter that can read up to 10.0 A,what shunt resistor is required?