Question

For charges q₁ and q₂ separated by a distance R the magnitude of the electrostatic force is given by ______.

Options

• F = `"q"_1/(4piepsilon_0"R"^2)`

• F = `("q"_1"q"_2)/(4piepsilon_0"R"^3)`

• F = `("q"_1"q"_2)/(4piepsilon_0"R")`

• F = `("q"_1"q"_2)/(4piepsilon_0"R"^2)`

Answer 1

For charges q₁ and q₂ separated by a distance R the magnitude of the electrostatic force is given by `underline("F" = ("q"_1"q"_2)/(4piepsilon_0"R"^2))`.

Explanation:

According to Coulomb’s law, the force between two point charges is

1. The force is directly proportional to the product of magnitude of charges i.e. `"F" prop |"q"_1| |"q"_2|`
2. The force is inversely proportional to the square of distance between two charges i.e. `"F" prop 1/"r"^2`(Inverse square law)
   Combining both
   `"F" prop (|"q"_1||"q"_2|)/"r"^2`   ....(1)
   OR
   `"F" = "k" (|"q"_1||"q"_2|)/"r"^2`   ....(2)
   Where k is a constant of proportionality known as force constant having different value in different systems
   k = `1/(4piepsilon_0) = 9 xx 10^9 ("Nm"^2)/"C"^2`