Electricity - I, V, Ω Flashcards
When investigating how the length of a wire affects the resistance of the wire, what are three variables that need to be controlled?
- Temperature of wire
- Thickness of wire
- Material of wire
What is the current like throughout a closed loop in a circuit?
Same everywhere
To find the resistance of a component, what are the two variables that need to be measured experimentally?
- P.d. across the component.
- Current flowing through it.
What is an alternating potential difference?
A potential difference that repeatedly changes direction across a wire.
When measuring the resistance of a piece of wire, it is hard to attach the crocodile clips to exactly 0 cm. What type of error does this cause?
Zero error - a type of systematic error
In an LDR, how does the resistance vary with light intensity?
As light intensity increases, resistance decreases.
How do you get a negative reading for potential difference?
Reverse the current.
What does an ohmic conductor graph look like?
A directly proportional line.
(A straight line going through the origin)
What does a filament lamp graph look like?
A curved line going from the bottom left to the top right.
What does a diode graph look like?
A straight, flat line staying at 0 until the top right quadrant, then it curves upwards.
Describe the properties in terms of current and potential difference for an ohmic conductor (1)
Current is directly proportional to potential difference.
How many directions does the current flow through a diode?
One
A diode has a very high ___ in the reverse direction.
reverse
For a thermistor, as temperature ___, resistance ___.
increases
decreases
For an LDR, as light intensity ___, resistance ___.
increases
decreases
