Thursday, June 12, 2008

Ch. 29 Electric Field - MQ -1

Prob: Determine the force between two electrons spaced 0.1 nm apart.

Concepts to be used

Coulomb's formula for the electric force between two charges.

(1) F = k*q1*q2/r²

q1,q2 charges
r = separation between charges
k = constant
In SI units k is measured to be 8.98755*10^9 N-m²/C²

The constant k is often written as 1/4πε0.
The constant ε0 is called the permittivity of the space and its value is

ε0 = 8.85419*10^-12 C²/N-m²

q1 = q2 = -1.6*10^-19 C
r = 10^-10 m

F = [9*10^9(1.6*10^-19)²]/(10^-10)²

= 9*2.56(10^(9-38+20))
= 23.04(10^-9)
= 2.304*10^-8

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