r (m)	Electric field E (V/m)
1	52.8
2	13.3
3	5.93
4	3.37
5	2.15
6	1.49
7	1.10
8	0.84

The constant of proportionality k is called Coulomb's constant. In SI units, the constant k has the value k = 8.99 10⁹ Nm²/C².

Using the table above, make a graph in Excel of voltage V and distance r to determine the constant k again using the appropriate trendline. (The same hint as above applies, but the work will be slightly different because the equation is different.)

Insert the graph and write down the k value that you found.

k constant from trendline equation=?

Accepted value of k constant =?