A neutron consists of one “up” quark of charge +2e/3 and two “down” quarks each having charge -e/3. If we assume that the down quarks are 4.1 × 10^-15 m apart inside the neutron, what is the magnitude of the electrostatic force between them?

Any thoughts?

Question

A neutron consists of one “up” quark of charge +2e/3 and two “down” quarks each having charge -e/3. If we assume that the down quarks are 4.1 × 10^-15 m apart inside the neutron, what is the magnitude of the electrostatic force between them?

Any thoughts?

anonymous · Answer

The question is wrong, but you can just use Coulomb's law to find the electrostatic force.

austinl · Answer

That is what I thought.
Use q_1=+2e/3
q_2&q_3=-e/3
d=4.1E-15 m

Any other thoughts beyond that?

anonymous · Answer

Oh, right, it's just asking about the force between the two negative charges. The positive one is irrelevant for this answer.

austinl · Answer

Okay, so only use q_2 and q_3 and the distance and plug those bad boys in and away I go?

anonymous · Answer

Yep

austinl · Answer

Okay, gimme just a minute and I will get back to you :)

austinl · Answer

I got 13.609 N, which when plugged in is evidently incorrect.

anonymous · Answer

I got 2 N

austinl · Answer

I just did it again and got the same thing. And for the record, 2 N is wrong as well.

anonymous · Answer

1.52 N, rather
Rounding

austinl · Answer

That is correct, could you show me how you had it plugged in?

I had:

F=((8.99E9)(-(1.60E-19))^2)/(4.1E-15)^2

anonymous · Answer

divide by 3^2

anonymous · Answer

the charge is e/3 and you put in e

austinl · Answer

Oh, stupid mistake.... Thank you very much.