A 6V DC voltage source is connected across both a 5kohm resistor and a 10 nF capacitor in series. The voltage drop across the resistor is what?

 

v(t) = V*exp(-t/RC)

V = voltage at source
R = resistance
C = capacitance

Dave

 

thanks but the time is not given

 

thanks but the time is not given

From the above equation the voltage across the resistor is a function of time, so it is pretty essential to the question - could it be asking you for the initial or final voltage across the resistor?

Dave

 

it is the final voltage across the resistor

 

it is the final voltage across the resistor

For the final voltage, and in the absence of a specific time, in the above equation use t = \(\infty\), therefore you get:

v(t) = 6*exp(-\(\infty\))

exp(-\(\infty\)) = 0, therefore in this ideal scenario the voltage across the resistor is 0V, i.e. the entire source voltage is across the capacitor.

Dave