Question

The nucleus of helium atom contains two protons that are separated by distance $3.0\times {10}^{-15}m$. The magnitude of the electrostatic force that each proton exerts on the other is:

• A. $20.6N$
• B. $25.6N$
• C. $15.6N$
• D. $12.6N$

Answer 1

The correct option is B $25.6N$

Charge of proton is $q_p=1.6\times {10}^{-19}C$
Distance between the ptoton is $r=3\times {10}^{-15}m$
The magnitude of electrostatic force between protons is

$F_e=\frac{q_p{q}_p}{4\pi {\epsilon }_0{r}^2}=\frac{9\times {10}^9\times 1.6\times {10}^{-19}\times 1.6\times {10}^{-19}}{{(3\times {10}^{-15})}^2}=25.6N$