Evaluative Flashcards
Find % uncertainty in capacitance value? (1mark)
Using C=t/kR
Combine (add) errors, should come to 16.5%
Find % difference between experimental value of C and the given (manufacturers) value? (1 mark)
(Δvalue/actual value) x100
Roughly 27.3%
Comment on reliability? (1mark)
Comment on:
Scatter
Spread
Anomalies
Comment on accuracy? (1mark)
Comment on:
-how close to true/manufacturers value (27.3%)
Limitation and improvement 1?
Limitation:
The person starting the timer when the switch is flipped off may be inaccurate due to human error, thus worsening the data.
Improvement:
To solve this problem, we could connect a timer into the circuit, so that when the switch is flipped the timer starts.
Limitation and improvement 2? (1 mark)
Limitation:
The person won’t accurately measure the voltage when the timer reaches 20 seconds.
Improvement:
The circuit could be connected to a data logger which will measure the voltage with respect to time. This would mean that after the experiment, the person can look at the time at 20seconds and see clearly what the voltage the circuit was at at 20 seconds.
Limit and improve 3? (1mark)
Limit:
When the capacitors are twisted together in the experiment, it creates a poor connection between them, which results in high energy loss due to high resistance in the wires.
Improvement:
To prevent this energy loss, the wires could be insulated and soldered together.
How to find percentage uncertainty in gradient? (1mark)
(Change in m/actual m value) x100
Roughly 4%
Limit and improve 4? (1mark)
Limit:
The manufacturers value of resistance for the resistor used may be inaccurate.
Improvement:
Before the experiment, run a test to measure the resistance of the resistor.
The gradient should be slightly steeper. Explain how this affects value of C? (1mark)
1) k should be slightly larger
2) since C=t/kR, if k increases, kR increases, therefore t/kR decreases so the final value of C is smaller.
