# physics

posted by .

An RC circuit contains a 3.9 kΩ resistor and a 5 µF capacitor. When the switch is first closed in the circuit, a maximum current of 1.5 mA flows in the circuit. Using Equation (1), find the time at which the current flow will have fallen to 1.0 mA.

• physics -

Hmmm.

I=V/R e^-t/rc is that you equation?

1.0=3.5e^t/rc
take the ln of each side

ln1.0-ln3.5=t/RC
solve for time t.

## Similar Questions

1. ### physics

which one of the following statements concerning an ac circuit is true?
2. ### Physics

Could someone please tell me what equations i am suppose to use to work out these problems. A capacitor in RC circuit has two overlapping plates of width 3.40 m and length 8.90 m separated by 2.60 cm. A dielectric of dielectric constant …
3. ### Science

Megan wants to determine if an electrical circuit has electricity flowing through it. Which of the following evidence is proof that the circuit has an electrical current?
4. ### Physics

The Circuit contains a resistor R1, Resistor with R2 and an inductance L in series with a battery of emf ε0=V0 . R2 having a switch in parallel, the switch S is initially closed. At t = 0, the switch S is opened, so that an additional …
5. ### Physics

A solenoid has N=1760.0 turns, length d=40 cm , and radius b=0.4 cm, (b<<d) . The solenoid is connected via a switch, S1 , to an ideal voltage source with electromotive force ϵ=7 V and a resistor with resistance R=25 Ohm …
6. ### Physics

A solenoid has N=1760.0 turns, length d=40 cm , and radius b=0.4 cm, (b<<d) . The solenoid is connected via a switch, S1 , to an ideal voltage source with electromotive force ϵ=7 V and a resistor with resistance R=25 Ohm …
7. ### Physics

A solenoid has N=1568.0 turns, length d=32 cm , and radius b=0.2 cm, (b<<d) . The solenoid is connected via a switch, S1 , to an ideal voltage source with electromotive force ϵ=13 V and a resistor with resistance R=25 Ohm …
8. ### Physics 112

A battery is connected in series with a R = 0.26 Ω resistor and an inductor, as shown in the figure below. The switch is closed at t = 0. The time constant of the circuit is τ = 0.10 s, and the maximum current in the circuit …
9. ### Science

One light bulb in a string of lights goes out this causes all other lights in string to go out. This is example of A. Resistor B. parallel circuit C. Closed circuit***** D. Series circuit When a switch is turned from the off to the …
10. ### electromagnetism

A series RLC circuit is connected to a a DC battery via a switch. #11A (3 points possible) A long time after the switch is closed, what is the current in the circuit?

More Similar Questions

Post a New Question