posted by .

How long will it take a charged 80-ìF capacitor to lose 20 percent of its initial energy when it is allowed to discharge through a 45 ohm resistor?

  • Physics -

    i mean 80 microfarads

  • Physics -

    The time constant for charge decay is
    RC = 3.6*10^-3 s, if your ì symbol means "micro"

    For 80% of the initial energy, the charge must decrease to sqrt(0.8) = 89.4% of the initial value.

    exp(-t/RC) = 0.894
    t/RC = .1121
    t = 4*10^-4 seconds

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    A capacitor of capacitance C= 10mF, is charged using a battery of potential V, through a resistor of resistance R = 250 ohms. the charge of the capacitor is given by Q(t)=CV[1− e ^ (−t/RC)] Find an expression for the current …
  2. physics

    A 20.0 \mu F capacitor initially charged to 20.0 \mu C is discharged through a 1.90 k\Omega resistor. How long does it take to reduce the capacitor's charge to 5.00 \mu C?
  3. physics

    A fully charged 98 uF capacitor is discharged through a 125 ohms resistor. How long will it take for the capacitor to lose 75% of its initial energy
  4. Physics

    A fully charged 90-µF capacitor is discharged through a 60-Ω resistor. How long will it take for the capacitor to lose 80% of its initial energy?
  5. Physics

    A 6 uF capacitor is initially charged to 100V and then connected across a 600 ohm resistor. a) what is the initial charge on the capacitor?
  6. physics

    how a bleeder resistor (R = 260 k) is used to discharge a capacitor (C = 85.0 µF) after an electronic device is shut off, allowing a person to work on the electronics with less risk of shock. Figure 20.47 (a) What is the time constant?
  7. Physic II

    Suppose a capacitor having a capacitance of C fully charged to a voltage V and then discharged through a resistor R. Derive the equation (in terms of C,V,and R) that shows how long a time the capacitor will take to lose 45 % of its …
  8. Physics

    How long will it take the voltage across the capacitor in an RC circuit to discharge 75% of its initial charged voltage if the resistor has a resistance of 450 kilo-Ohms and the capacitor has a capacitance of 49 micro-farads?
  9. Physics

    A 14.1 μF capacitor is charged to a potential of 45.0 V and then discharged through an 80.0 Ω resistor. (a) How long after discharge begins does it take for the capacitor to lose 90.0% of the following?
  10. Physics

    A charged capacitor,C=10e-6 F, with an initial stored energy of 3.5J, is discharged across a resistor, R. The charge on the capacitor drops to 40% of its maximum value in time, t=8.2s, from the instant the switch is closed (t=0). Find …

More Similar Questions