RESISTORS Flashcards
Why might a high resistance be bad?
Energy is wasted
how is high resistance useful?
we sometimes need to add extra resistance to dim a lamp. It also reduces the amount of electrical energy that is transmitted/passed.
If we wanted to dim a lamp we can either:
Use a cell with a lower potential difference/voltage or
extra resistance could be added to the circuit.
In a circuit, a resistor is added in series with a lamp. Potential difference is being shared between the lamp and the resistor, this means…
less electrical energy is transferred to the lamp making it dimmer/ not as bright.
In a circuit, there is a potential difference of 10V of a resistor and a current of 0.1A on an ammeter. Calculate the resistance of the resistor.
=100Ω
Resistance(Ω)= Potential difference(V) / current(A)
resistance(Ω) = 10V / 0.1A
= 100Ω
When increasing potential difference across a resistor , we measure the current flowing and plot this on a graph. In each experiment, the p.d is increased by 10 volts, we do this for a number of times and plot it on a graph. explain the results on the graph.
After plotting the results on a graph, the graph shows a straight line which represents the resistance being constant. The resistance does not change if we can increase the current
The resistance in a circuit will only stay constant as we increase the p.d/voltage if…
the temperature stays constant
During the experiment in which we increase potential difference across a resistor and measure the current flow, we start off with 0V which gives us a current of?
This is because…
In the second time round, we increase the pd by 10V, this give us a current of…
In the third time round we increase the pd by another 10V giving us 20V, this then gives us a current of?
We do this a few more times then plot this information on a…
0A
If p.d is 0V, electrons have no energy so they are unable to move through the resistor.
0.1A
0.2A
We do this a few more times then plot this information on a graph.
