Find resistivity by C++

Question

A student wants to measure a resistivity of a material of certain wire of radius 2 mm, and length of 25 cm. He got the following data

Voltage (V): 100, 90, 80, 70, 60, 50, 40, 30, 20,7 Current (A): 11, 8, 7, 6, 5.7,5, 3.9, 2.3, 2.1, 1.1. Find the resistivity?

Answer 1

Resistivity R = U / I

Answer 2

https://code.sololearn.com/c67fuNOJUv45/?ref=app
I hope after you understand it try to write it from scratch 💪🏻

Answer 3

JaScript No,
Resistivity=Resistance*area/length

Answer 4

Oroob Mustafa okay, this is due to my not so good English in the special terms. I would say a resistance‘s material constant.
So is right: Resistance R = U / I
and than you can calculate with the
„Resistivity“ = U*area / length / I / 2
Where do you have problems with your code?
By the way please provide link here to your code.

Answer 5

@Wedad Saleh instead of int r = 2 you need to use float r = 0.002 because of unit conversion from mm to m.

@Oroob Mustafa
Now the loop in Wedad Saleh's code doesn't increment so it only calculates the resistivity for the first pair of data. It can be used to calculate an average for the resistivity. But I think you can try to do that yourself and ask for more specific help.

Answer 6

Oroob Mustafa You can find area and length and Resistance is Voltage / Current .
Maybe all those voltages and currents need to be added.

Answer 7

The resistivity also depends with the temperature (and higher currents mean higher temperature) but in this case the measurement errors seem to be too large for this kind of complication.

Answer 8

It would be very unnatural to use a mix of two units of length in the result. It's like having one more step to the answer.
So we need to preferably convert all values in SI units.
The unit in SI for resistivity is ohm metre (that is ohm * metre).

Answer 9

Oroob Mustafa if you need a small challenge while writing the program for yourself, from scratch, try to provide a correct numerical value followed by the unit in SI (ohm metre) and a measure of the accuracy of the measurements such as the standard deviation.
Any physics teacher would be happy to see your answer.

Answer 10

Wedad Saleh

Answer 11

Good