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since v is propotional to i it is a straight line

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Q: Why ohm's law V-I graph always be straight line?
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How do you plot ohms law graph of potential difference versus current?

The current is represented by the horizontal (x) axis, and the potential difference is represented by the vertical (y) axis.If the resulting graph is a straight line, then it confirms that the circuit is obeying Ohm's Law. If the resulting graph is a curve, then the circuit does not obey Ohm's Law.The gradient at any point along of the resulting line represents the resistance of the load for that ratio of voltage to current.


Is ohms law true for all materials?

Most definitely NOT! For Ohm's Law to apply, the ratio of voltage to current MUST be constant for variations in voltage. And this is only true for a small number of materials we call 'ohmic' or 'linear' materials -meaning that if we plotted a graph of voltage against current for changes in voltage, we'd end up with a straight line (linear) graph. But most materials are 'non-ohmic' or 'non-linear' -in other words, the resulting graph is NOT a straight line. It can be argued that Ohm's Law, therefore, is not a 'law' at all! Perhaps it's time it was scrapped?


What is an example of a circuit that doesnt obey Ohms Law?

The easiest circuit that does not obey Ohm's law is a circuit that has a resistance that depends on temperature. For example, if you take a light bulb and draw a current-vs-voltage, you see that in the beginning (under low voltage) the graph is NOT a straight line, but under high voltage the graph is linear. This is because the resistance depends on temperature. the equation V=IR isn't consistent with the graph's shape.


What are infinite ohms?

That is an open line.


What is the impedence of telephone line?

In the USA, should be 500 or 600 Ohms. It is 600 ohms as standard


What is the amount of power loss on a transmission line that is transmitting 10 MW at 500 kV with 1000 ohms?

Line current = 10MW / 500kV = 20A Assuming the 1000 ohms is the resistance of the entire transmission line, end to end. Power loss = line current ^ 2 * line resistance = 20A ^ 2 * 1000 ohms = 400 KW


What obeys ohms law nichrome thermistor or diode?

Ohm's Law only applies when the ratio of voltage to current is constant for variations in voltage. If you were to plot a graph of current against voltage, and the result is a straight line, then Ohm's Law applies; if the result is a curved line, then Ohm's Law does NOT apply.Ohm's Law is NOT a universal law; in fact, if barely qualifies as a 'law' at all because, in most cases, it does not work!Nichrome alloy is designed to retain a constant resistance over a wide range of temperatures. So it is considered to be 'ohmic' or 'linear' because, when plotting current against voltage, it produces a straight-line graph, for variations in voltage. So, nichrome obeys Ohm's Law.Thermistors and diodes produce curved graph lines and, so, are considered to be 'non-linear' or 'non-ohmic', and do NOT obey Ohm's Law.


How do you find resistance by a graph?

To find resistance from a graph of voltage vs. current, you can calculate the slope of the graph. Resistance is equal to the slope, so you can divide the voltage by the current to determine the resistance. The unit of resistance is ohms (Ω).


Can you describe an experiment to demonstrate Ohms Law?

You need a d.c. variable-voltage supply, a voltmeter, an ammeter, and a resistive load. The voltmeter must be connected in parallel with the resistive load, and the ammeter in series.Gradually increase the voltage across the load, in discrete (uniform) steps. For each step, note the values of voltage and corresponding current.Use your results to plot a graph, with voltage along the horizontal axis, and current along the vertical axis.If the resulting graph is a straight line, then the load is 'linear' or 'ohmic', and obey's Ohm's Law. If the resulting graph is a curve, then the load is 'non-linear' or 'non-ohmic', and does NOT obey Ohm's Law.The reciprocal of the slope of the graph, at any point along its length, represents the resistance at that point. For a straight-line graph, the resistance will be constant (obeying Ohm's Law); for a curved-line graph, the resistance will vary along its length (does no obey Ohm's Law).Remember that Ohm's Law is not a universal law, in other words not all loads obey Ohm's Law - these include metals such as tungsten (used to make the filaments of incandescent lamps), electrolytes, and most solid state devices, such as diodes, etc.


For a quarter wavelength ideal transmission line of characteristic impedance 50 ohms and load impedance 100 ohms the input impedance will be?

50 in parallel with 100 ohms. Dza10 answer: Rin = 50^2 /100


What is the shape of the graph between volt and electric charge where Volt is the potential difference between the ends of an ohmic resisitor and electric charge is the current flowing through it?

-- If one axis of your graph represents the current flowing through the resistor, then label it "Current", not "Electric charge". There's a big difference between charge and current. -- Ideally, the current through an ohmic resistor is a linear function of the voltage across its ends, namely a direct proportion with the resistance being the constant of proportionality. -- Ideally, the graph is a straight line, with slope equal to the resistance in ohms, and y-intercept of zero. -- In reality, the resistor dissipates energy at the rate of (voltage) x (current) watts. It must warm up as a result, and the change in its temperature always has some effect on its ohmic resistance.


If volts change then amps and ohms stay the same?

The ohms will usually stay the same unless the Amps are somehow effecting the temperature. The Amps will always change with the volts.