Exam 26: Direct Current Circuits

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 capacitor.

An RC circuit has a time constant of 2.10 s.At t = 0,the capacitor is fully charged.At what time will the voltage across the capacitor be half of its initial value?

Two identical 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,and 11 ns later the voltage across the resistor pair is 2.5 V,what is the resistance of each resistor?

A 24-V battery is attached to a 3.0-mF capacitor and a 100-ohm resistor.What is the energy dissipated as heat inside the resistor while the capacitor is charging.

Which of the following will reduce the decay time in an RC circuit?

In the movie Back to the Future,time travel is made possible by a flux capacitor,which generates 1.21 GW of power.Assuming that a 3.00-F capacitor is charged to full charge with a 12.0-V car battery and is discharged through a resistor,what is the resistance necessary to produce a peak power output of 1.21 * 10⁹ W in the resistor?

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.Determine the energy stored in the capacitor when switch S has been closed for a long time.

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 effective resistance of the circuit with the DMM connected?

A galvanometer reads I = 6 mA full scale and has an internal resistance r = 9.1 ohms.If you want to use it to read 7.1 volts full scale,what resistor,R,should you use in series with it?

A 2-µF capacitor is connected in series with a 1.2-M $\varOmega$ resistor and a 5-V battery for a long time.What is the current in the resistor 1s after disconnecting the battery?

Beginning with an uncharged capacitor in an RC circuit,how long would it take,in multiples of time constant $\tau$ ,for the capacitor to be 98% charged?

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 capacitor 0.16 seconds after the circuit is connected to the battery?

Use Kirchhoff's rules to solve for i1 (in a)in the circuit shown above where i = 15.0 A,V = 14.0 V,and R = 6.00 $\varOmega$ .Note that this drawing represents a subset of a full circuit.

A 24-V battery is attached to capacitor and a 100-ohm resistor.If 1.73 J of energy are dissipated by the resistor while the capacitor is charging,what is the capacitance of the capacitor?

Consider an RC circuit with a capacitance of 150 $\mu$ 0F,a resistance of 1 MΩ and connected to a 200-V power source for a long time.The power supply is disconnected and shorted.How long should one wait before the voltage across the capacitor drops to below 50 V?

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 parallel with the first,how much current is drawn from the battery?

In the circuit shown,determine the charge on each capacitor when switch S has been closed for a long time,where R₁ = 1 k $\varOmega$ ,R₂ = 2 k $\varOmega$ ,C₁ = 1 $\mu$ F,and C₂ = 2 $\mu$ F.

Lithium polymer batteries have revolutionized the battery field due to their light weight,high energy density (about four times greater than nickel-cadmium or nickel-metal-hydride cells)and low internal resistance.At 25 ^$\circ$ C a three cell lithium polymer battery has no load voltage of 11.1 V and an internal resistance of 300 m $\varOmega$ .If the battery is used to power a device that needs a minimum of 10.0 V,e.g.,it will not work if the applied voltage is below 10.0 V,what is the minimum resistance of that device?

When being used to measure voltage,a voltmeter should be connected in

In the circuit shown in the figure,the switches S1 and S2 are initially open and the 20-mF capacitor has a charge of 100 mC.About how long will it take after switch S1 is closed (switch S2 remains open)for the charge on the capacitor to drop to 5 mC?