An uncharged series RC circuit is to be connected across a battery.For each of the following changes, determine whetherthe time for the capacitor to reach 90% of its final chargewould increase, decrease, or remain unchanged. Indicateyour answers with “I,” “D,” or “U,” respectively. (a) The RCtime constant τ is doubled. (b) The battery voltage is doubled.(c) A second resistor is added in series with the original resistor.

An uncharged series RC circuit is to be connected across a battery.For each of the following changes, determine whetherthe time for the capacitor to reach 90% of its final chargewould increase, decrease, or remain unchanged. Indicateyour answers with “I,” “D,” or “U,” respectively. (a) The RCtime constant τ is doubled. (b) The battery voltage is doubled.(c) A second resistor is added in series with the original resistor.

University Physics Volume 2

18th Edition

ISBN:9781938168161

Author:OpenStax

Publisher:OpenStax

Chapter10: Direct-current Circuits

Section: Chapter Questions

Problem 52P: A 2.00- and a 7.50F capacitor can be connected in series or parallel, as can a 25.0- and a 100k...

See similar textbooks

Similar questions

The timing device in an automobile's intermittent wiper system is based on an RC rime constant and utilizes a 0.500F capacitor and a variable resistor. Over whatrange must R be made to vary to achieve time constants from 2.00 to 15.0 s?
A 2.00- and a 7.50F capacitor can be connected in series or parallel, as can a 25.0- and a 100k resistor.Calculate the four RC time constants possible from connecting the resulting capacitance and resistance in series.
Consider an RC circuit in which R = 0.5 Ω, C=0.1 F, and Eo = 20 V. Given that the capacitor haszero initial charge, determine the current in the circuit after 0.25 seconds.
Regarding the units involved in the relationship τ = RC, verify that the units of resistance times capacitance are time, that is, Ω ⋅F=s.
Using the exact exponential treatment, find how much time (in s) is required to charge an initially uncharged 120 pF capacitor through a 67.0 MΩ resistor to 91.0% of its final voltage. __________s
Consider an initially uncharged capacitor in an RC circuit. The resistance is 20,000 Ohms and the capacitance is 500 x10• F. If the source potential being used to charge the capacitor is 15 V, how long after charging begins will the power delivered to the resistor be 25 % of its maximum value?
A simple RC circuit consists of a 1-μF capacitor in series with a 3000-Ω resistor, a 6-V battery,and an open switch. Initially, the capacitor is uncharged. How long after the switch is closedwill the voltage across the capacitor be 3.8 V?
Consider a series RC circuitas in Figure P18.35 forwhich R = 1.00 MΩ, C =5.00 µF, and ε = 30.0 V.Find (a) the time constantof the circuit and (b) themaximum charge on thecapacitor after the switch isthrown closed. (c) Find thecurrent in the resistor 10.0 safter the switch is closed.
Suppose that a simple RC circuit composed of a resistor andcapacitor connected in series to a constant voltage source started chargingat time t = 0. Find the number of time constants needed to charge thecapacitor 99.9% of the maximum charge.
Suppose the wire has a 10Ω resistance (which is almost certainly an overestimate) and the voltmeter has a 1MΩ resistance (1Ω=1s/F). Given that our capacitances are of order ~10μF, compute the time constant for each resistance: this is essentially the time it takes for current to "go through" that component. From these timescales, consider: of the two processes described above (the quick change in voltage and the slow change in voltage), which process is controlled by each component's resistance? On very long timescales (minutes-to-hours), the voltmeter can essentially be considered as another wire - current can pass through it given enough time. Based on this, if we were to leave the capacitors in Part I in the left (capacitors charged) position for a very long time, what voltages would you observe on each capacitor? What if we left the capacitors in Part II in the right (capacitors connected together) position for a very long time?
After the capacitor in an RC circuit had acquired charges, the battery was removed. As aresult, the capacitor discharged. The time constant of the RC circuit is 1.25 s. Find the timeafter the battery was removed, such that the charge in the capacitor is 65% of its initialcharge.
Consider two identical simple RC circuits each composed of acapacitor ( 2.49 mF), a resistor ( 25.3 kΩ), and a constant DC source( 19.7 V). At time t = 0, one capacitor, initially fully charged, is madeto discharge through the resistor in its RC circuit, with the DC sourcedisconnected. At the same time, the other capacitor, initially uncharged, is made to charge through the DC source in its RC circuit, with theconnected resistor. The time at which the two capacitors will have equalcharge is most nearly