Resisitance Flashcards
What happens when a resistor is connected in series?
The total resistance of the circuit is increased because the pathway becomes harder for current to flow through.
How does the amount of potential difference correlate to the number of resistors?
The potential difference from a cell is shared between the resistors, but it may not be shared equally. There will be greater potential difference across resistors with higher resistances.
What happens when a resistor is connected in parallel?
The total resistance of the circuit is less than the resistance of the individual resistors. This is because there are now more paths for the current.
What does a potential difference across a filament lamp cause it to do?
It causes a current to flow through it. The current causes the filament to heat up and glow. The greater the potential difference, the more current flows and the hotter and whiter the filament gets
What happens to a filament lamp after it heats up and what does this mean for the proportion of potential difference to charge?
Its resistance increases. This means that when the potential difference changes, the current does not change by the same percentage (the two variable are not in direct proportion)
How does resistance change in a light dependent resistor (LDR)?
It has a high resistance in the dark but the resistance gets smaller when the light intensity increases.
How does resistance change in a thermistor?
They have high resistances at low temperatures but as the temperature increases the resistance decreases.
