An electron is negatively charged so I don't think it's a problem getting a negative value for the charge. As for the answer, 2.93 is as close to 3 as makes no difference (considering how small a mass you're talking about) so I'd say that's all ok...You're supposed to get integer multiples of...
This is Millikan's Oil Drop Experiment - where the oil drop is 'suspended' between parallel plates. Normally the electric field is: E=N/C, ie force per coulomb of charge. In parallel plates the field is basically constant, and can instead be calculated by E=V/d. So if you have the distance and...
Fairly simple question, I just couldn't think of a suitable explanation for it.
In white dwarfs, neutron stars etc gravity is balanced by high outward pressure of fermions, which are in a confined space, so have v. high velocities. My question is, if you placed a heavy weight on an ordinary...