Table of Contents
- 1 What does it mean when there is a straight line on a current vs voltage graph?
- 2 Is a plot of current vs voltage always a straight line?
- 3 What is the relationship between the slope of the voltage vs current graph and the resistance of the wire in the circuit?
- 4 Why is voltage directly proportional to current?
- 5 Is voltage always directly proportional to current?
- 6 Why is voltage not directly proportional to current?
What does it mean when there is a straight line on a current vs voltage graph?
Current is directly proportional to voltage and inversely proportional to resistance. A resistor is ‘Ohmic’ if as voltage across the resistor is increased, a graph of voltage versus current shows a straight line (indicating a constant resistance). The slope of the line is the value of the resistance.
Is a plot of current vs voltage always a straight line?
For circuits with stable resistances, the plot of current over voltage is linear (I=E/R). In circuits where resistance varies with changes in either voltage or current, the plot of current over voltage will be nonlinear (not a straight line).
What is the relationship between the slope of the voltage vs current graph and the resistance of the wire in the circuit?
The relationship between voltage and current is Ohm’s Law, and the slope of the line from a graph of the two is the value of the resistance in the circuit. The Ohm’s Law equation can be represented in three ways: R = V / I (resistance = voltage divided by current)
Why is a resistor graph straight?
Because the resistor value is fix or does not change. When you increase the voltage, you will have a correspond increase of current which is I=E/R. Therefore the graph is linear or a straight line with a fix slope.
Why is the voltage current relationship different for a light bulb vs a resistor?
The relationship between current and voltage is direct – as voltage increases, current increases. The relationship between current and resistance is inverse. As resistance increases, current decreases (for a fixed voltage). The light bulb filament changes temperature and therefore changes resistance.
Why is voltage directly proportional to current?
This is now known as Ohm’s Law. One way Ohm’s Law can be stated is: “a current flowing through a conductor is directly proportional to the voltage, given the temperature of the conductor remains constant”. Therefore, if the resistance is kept constant, then doubling the voltage doubles the current.
Is voltage always directly proportional to current?
The relationship between current, voltage and resistance is expressed by Ohm’s Law. This states that the current flowing in a circuit is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit, provided the temperature remains constant.
Why is voltage not directly proportional to current?
We can increase the voltage with nothing connected to it so the current stays at zero which means there is no proportion between the voltage and current.