CP11 PD accross a capacitor

Question 1

What equipment is used?

Answer 1

Set up a circuit with a DC power supply, high resistance resistor 470kohms, switch, capacitor, ammeter and a voltmeter around the (initially discharged) capacitor
Close the switch allowing the capacitor to charge
Change the switch so that it discharges and starts the stopwatch
Lap the timer when the V reaches a predetermined level
Repeat for a different predetermined value (do it multiple times for each value)
Graph of lnV against t

Question 2

Safety

Answer 2

Make sure the capacitor is facing the right way so that it doesn’t explode
Use low voltages

Question 3

How to reduce the uncertainty?

Answer 3

Measuring a larger value for time reduces uncertainty and the effect of reaction time
Do a trial discharge so that you can choose a suitable time interval to take readings
Use a data logger and computer

Question 4

How to determine the length of error bars for time?

Answer 4

Take a middle value and find the range of the repeat readings.

Question 5

Why might using an oscilloscope to measure V be advantageous?

Answer 5

It has a high resistance
The square wave is much quicker
It can measure much smaller values.