Coulomb's Law (Electric Force) Video Lessons

Concept

# Problem: An atomic nucleus has a charge of +40e. An electron is 10-9 m from the nucleus. What is the force on the electron?A) 2.9 nN B) 9.2 nNC) 3.7 nN D) 1000 C E) 6.8 nN

###### FREE Expert Solution

From Coulomb's law:

$\overline{){\mathbf{F}}{\mathbf{=}}\frac{\mathbf{k}{\mathbf{q}}_{\mathbf{1}}{\mathbf{q}}_{\mathbf{2}}}{{\mathbf{r}}^{\mathbf{2}}}}$

• k = 8.99 × 109 Nm2/C2 (Coulomb's Constant)
• q1 = 40 (1.6 × 10-19) C
• q2 = 1.6 × 10-19C
• r = 10-9m

Substituting gives:

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###### Problem Details

An atomic nucleus has a charge of +40e. An electron is 10-9 m from the nucleus. What is the force on the electron?

A) 2.9 nN

B) 9.2 nN

C) 3.7 nN

D) 1000 C

E) 6.8 nN