The two most important minerals you need to do the test are <span>Corundum and quartz. You use that to do scratch test</span>
Answer:
I'm not sure but I think it's 35-39
A sphere is charged with electrons to −9 × 10−6 C. The value given is the total charge of all the electrons present in the sphere. To calculate the number of electrons in the sphere, we divide the the total charge with the charge of one electron.
N = 9 × 10−6 C / 1.6 × 10−19 C
N = 5.6 x 10^13