When a 470 micro farad capacitor is discharged through a fixed resistor R, the pd across it decreases by 80% in 45 s. Calculate the time constant of the circuit
Using the equation V=V0e-t/RC where RC is the time constant to be calculated: We know that the pd decreases by 80%, therefore the pd remaining, V is 0.2*V0. Putting this into the equation above: 0.2=e-t/RC, rearranging for RC gives RC=-t/ln(0.2), and substituing t=45s, we have: RC=28 s. The answer reflects the time it takes for the potential difference across the resistor to decrease to 37% of its original value when the capacitor is discharged through it.
PK
Related Physics A Level answers
All answers ▸In some SUVAT questions, they ask for 2 time solutions and I can only find 1. What am I missing?
Two cars start at point A. Car 1 moves in a direction at 5 m/s. After 10 seconds car 2 accelerates in the same direction as car 1 at 2m/s^2. At what time after car 1 starts moving and distance from A does car 2 pass car 1?
Steel has a density of 8030kg/m^3. Show that a steel ball with a diameter of 5cm weighs approximately 5N
Single electrons travelling at 550 ms^-1 are passed through a diffraction grating with a spacing between the slits of 2.5 micrometers. What would the angle between the zeroth and first maximum of the resulting interference pattern be?