Using Min and Max slope method to determine uncertainties

[hibachii]

Homework Statement

The graph below shows the potential (V) applied to, and the current I(mA) drawn by, an electrical circuit. Use the max and min slope method to determine the:
a) equation of line of best fit of the graph below (answer must be and equation relating to V and I). Your answers must include uncertainties
b)equivalent resistance of the circuit and the uncertainty in this resistance.

Homework Equations

V=IR

The Attempt at a Solution

I have no idea on how to tackle this question. We are given this much info on the question and left to do it by ourselves. PLease help!

 

[clementc]

Well you know Ohm's law, which is just V=IR

a graph of V on the vertical vs I on the horizontal will give R as the gradient yeah?
It's like V=IR is in the form of a straight line y=mx+b, where y is the V and the x is the I. Hence the gradient m represents R in this case.
the y intercept b is zero in ohm's law V=IR because it's assumed that when V=0, I =0.
However you might have a systematic error and hence in experimental values your line of best fit most often will not pass exactly through (0,0). Please please NEVER force a line of best fit through the origin.

Anyway, max and min slope. Did they give you the uncertainties for the current and voltage? Only with them can you graph the lines of best and worst fit

 

[hibachii]

no they did not. they told us to work it out using max and min slope method. The only thing close to working out uncertainty is that current is measured in mA.

 

[clementc]

lmao that's slightly dodgy =P
the fact that it's measured in milliamps doesn't really help with the uncertainty because it still doesn't tell you the limit of reading

in that case i think you should just like try and draw the line of best fit, then two lines of worst fit that kind of look reasonable? =S (like not too wildly off)
dodgy question =(
what do other physics forumists think? =D

 

[rwisz]

I can provide a response to this question by breaking down the steps for using the min and max slope method to determine uncertainties.

Step 1: Plot the data points on a graph with V (potential) on the x-axis and I (current) on the y-axis.

Step 2: Determine the maximum and minimum slope of the line of best fit by drawing two lines through the data points that have the steepest and shallowest slopes, respectively.

Step 3: Calculate the uncertainty in the slope by subtracting the minimum slope from the maximum slope. This will give you the range of possible slopes for the line of best fit.

Step 4: Use the equation V=IR to determine the equation of the line of best fit. The slope of the line will be the resistance (R) of the circuit.

Step 5: Calculate the uncertainty in the resistance by multiplying the uncertainty in the slope by the maximum value of V in the data points.

Step 6: The equivalent resistance of the circuit will be the average of the maximum and minimum resistance values, with the uncertainty being half of the range between the two values.

In summary, the equation of the line of best fit will be V=IR, with the resistance (R) being the slope of the line. The uncertainty in this resistance can be determined by using the min and max slope method and taking into account the range of possible slopes. The equivalent resistance of the circuit can be calculated by taking the average of the maximum and minimum resistance values, with the uncertainty being half of the range between the two values.