Exam 26: Direct Current Circuits

An old 9.0-V battery produces a potential difference of 9.0 V when checked with a voltmeter.If the internal resistance is 14.3 Ω and a 100 Ω resistor is connected across the battery leads,what is the voltage across the battery's leads?

During a physics demonstration,a fully charged 98-µF capacitor is discharged through a 125- $\varOmega$ resistor.How long will it take for the capacitor to lose 75% of its initial energy?

In the circuit shown,with the switch open the capacitor is completely uncharged.The switch is closed for a long time.The current through the circuit is 0.2 A.Determine the potential difference across the unknown resistor.

In the circuit shown,R₁ = 5 $\varOmega$ ,R₂ = 10 $\varOmega$ ,and R₃ = 15 $\varOmega$ ,and $\varepsilon$ ₁ = 10 V,and $\varepsilon$ ₂ = 15 V.Using Kirchhoff's loop and junction laws,determine the currents I₁,I2,and I₃ flowing through R₁,R₂,and R₃,respectively,where the direction of each current is as indicated in the figure.

You have an RC circuit with the switch initially open.When the switch is closed which of the voltage as a function of time plots most accurately represents the charging of the capacitor?

In the circuit shown,with the switch open the capacitors are completely uncharged.The switch is closed for a long time.The current through the circuit is 0.2 A.Determine the potential difference across the 8.0 $\varOmega$ resistor.

Two identical 2.5- $\varOmega$ resistors are parallel to each other,and the combination is in series with a 5.0-nF capacitor,in a circuit with a switch open.If initially 15.0 V is across the capacitor,how long after the switch is closed will the voltage across the resistor pair be 2.5 V?

A capacitor of capacitance C and a resistor of resistance R are connected in series.At time t = 0 the combination is connected across a battery of negligible internal resistance.When is the current through the resistor equal to half of its maximum value?

In the circuit shown,R₁ = 10 $\varOmega$ ,R₂ = 4 $\varOmega$ ,R₃ = 10 $\varOmega$ , $\varepsilon$ = 10 V,and capacitor has a capacitance C = 2 $\mu$ F and the switch S has been closed for a long time.After switch S is opened,how much total energy is dissipated through R₃?

A 9.0000-V battery is used to produce a current through two identical resistors in series,each having a resistance of 150.00 k $\varOmega$ .A handheld digital multimeter (DMM)is used to measure the potential difference across the first resistor by placing probe leads at each end of this resistor.Typical DMMs have an internal resistance of 10 M $\varOmega$ .What is the current in the circuit with the DMM connected?

When being used to measure current,an ammeter should be connected in

A 24-V battery is attached to a 3.0-mF capacitor and a 100-ohm resistor.If the capacitor is initially uncharged,what is the charge on the capacitor 0.21 seconds after the circuit is connected to the battery?

A 24-V battery is attached to a 3.0-mF capacitor and a 100-ohm resistor.If the capacitor is initially uncharged,what is the voltage across the resistor 0.16 seconds after the circuit is connected to the battery?

A voltmeter must be placed in parallel with the circuit element whose voltage is to be measured.An ideal voltmeter therefore has

What is the current in the 4.0 $\varOmega$ resistor in the circuit shown in the figure?

A direct current power supply is connected to a circuit containing one resistor,and 1.5 A is drawn.If a second identical resistor is connected to the power supply in series with the first,how much current is drawn from the battery?

A galvanometer reads I = 6 mA full scale and has an internal resistance r = 9.1 ohms.If a resistor,R = 425 $\varOmega$ is connected in series with the galvanometer,what is the full scale voltage of the device?

If the 2- $\mu$ F capacitor in the circuit shown initially had a potential difference of 10 V across its plates,how much charge is left on it after the switch has been closed for a duration equal to one half of the time constant?

The ammeter your physics instructor uses for in-class demonstrations has a resistance R_g = 60 $\varOmega$ and requires a current of 1.0 mA for full-scale deflection.The same ammeter can be used to measure currents of much greater values by wiring a shunt resistor of relatively small resistance,R_p ,in parallel with the ammeter.The value of the shunt resistance that allows the ammeter to be used to measure a current of 12 A at full-scale deflection is

A resistor and capacitor are connected in series in an open circuit.If a second identical resistor is connected in series in the circuit,the time constant for the circuit will