Physics

posted by .

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 passing through the resistor as a function of time, and make a graph clearly indicating the initial values. how long will it take for the current passing through the resistor to drop to 37% of its max value?

  • Physics -

    Current is the derivative of the capacitor charge.

    I(t) = dQ/dt = CV/(RC) exp(-t/RC)
    = (V/R) exp(-t/RC)

    Current is 1/e = 37% of the initial value when t/RC = 1. That is called the time constant.

    You will have to draw you own graph.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. physics

    Having trouble with this one: A capacitor having a capacitance of 10uF is charged by 100v battery. A.)Calculate the charge on the capacitor?
  2. SCience

    An RC-circuit has a time constant of 6x10-3 seconds. The capacitor stores a maximum energy of 8 J, when charged using a 3-Volt battery. Using the same battery, we want to increase tenfold the amount of stored energy, while keeping …
  3. physics

    A capacitor that powers the flash in a camera is charged using 6.0 V battery. after that capacitor is charged, it is discharged through the flashbulb in just 1.0 microsec. with avg power output of 20 w. whats is the capacitance?
  4. Physics

    An RC-circuit has a time constant of 6x10-3 seconds. The capacitor stores a maximum energy of 8 J, when charged using a 3-Volt battery. Using the same battery, we want to increase tenfold the amount of stored energy, while keeping …
  5. Physics

    Two circular metal disc each of 3.00 cm diamter are 1.5 mm apart make a capacitor. A)What is the capacitance of this capacitor if it is in series to a 25 V battery?
  6. College Physics 2

    A parallel-plate air capacitor is made from two plates 0.250 m square, spaced 0.70 cm apart. It is connected to a 140 V battery. a) What is the capacitance?
  7. Physics

    A q = +3.00 mC test charge is placed inside a constant uniform electric field created in a parallel plate capacitor connected to a battery of unknown voltage.   The capacitor is made of two parallel plates each with area equal to …
  8. Physic II

    Suppose a capacitor of C=2.0 uF with no excess charge on it is suddenly connected in series with a resistor of R=447 ohms , and an ideal battery of voltage V=25 V . How long will the capacitor take to gain 80% of the charge it will …
  9. 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?
  10. Physics

    A parallel plate capacitor has a rectangular plates with length 5cm and width 3cm. They are separated by a distance 12m and hooked up to a 20V battery A.) what is the area of each plate in m^2 B.) assuming nothing else is present on …

More Similar Questions