Question

Two charge spears are 20 cm apart and extract an attractive force of 8x10^-9 N on each other. Which will be the force of attraction when the Spheres are moved to 10 cm apart ?

Answer 1

3.2 × 10⁻⁸ N.

Step-by-step explanation:

By Coulomb's Law, the magnitude of the electromagnetic force between two point charges is inversely proportional to the square of their separation,
`r`. In other words,

`\displaystyle (F_1)/(F_2) = {\left((r_2)/(r_1)\right)}^(2)`.

• Initial electromagnetic force
  `F_1 = 8* 10^(-9)\;\text{N}`;
• Initial Separation
  `r_1 = 20\;\text{cm}`;
• Final Separation
  `r_2 = 10\;\text{cm}`.

Final electromagnetic force:

`\displaystyle F_2 = F_1 \cdot \left((r_2)/(r_1)\right)^(2) = 8* 10^(-9)* \left( (20)/(10)\right)^(2) = 3.2* 10^(-8)\;\text{N}`.