The force between charge $-q$ at point $D$ and $q$ at point $B$ is also attractive, lies along the diagonal of $BD$ and points inward. Problem (3): What is the magnitude of the force that a ${\rm 25\, \mu C}$-charge exerts on a ${-\rm 10\,\mu C}$ charge ${\rm 8.5\, cm}$ away? Physics : Electrostatics - Solved Example Problems: Coulomb's Law. Find more Education widgets in Wolfram|Alpha. Lets give the radius 0.04 the variable a = 0.04m. Calculated values and results can be shared to social media, mail, messages and other sharing apps. Solution: applying Coulomb's law, we have \begin{align*} F&=k\frac{q_1 q_2}{r^2}\\&=\big(9\times 10^9\big)\frac{(0.0025)(0.0025)}{(8)^2}\\&=879\quad {\rm N}\end{align*}. Again, use this line of reasoning to determine the direction of the force and not the sign in Coulomb's Law. q1 is the magnitude of the first charge. This law takes a look at the forces which are created between two charged objects. (a) Find the magnitude of each charge? Coulomb's law get the magnitude of the force between two charges. Coulomb's law explains the electrostatic law between two point charges placed at a difference. (a) Since the charges are like so the electric force between them is repulsive. Found inside – Page 265Solution : Total number of lines = 10-10 x 1020 1010 1010 47102 Lines per ... By coulomb's law we can calculate E for a given charge , but the Gauss's law ... window.jQuery || document.write('