Constants and magnitudes

Exercise and reference answers

Questions

1. Question

   The approximate value of k is

   Choices

   1. 8.854 × 10⁻¹² N m² C⁻²
   2. 6.67 × 10⁻¹¹ N m² C⁻²
   3. 9 × 10⁹ N m² C⁻²

   Correct choice

   9 × 10⁹ N m² C⁻²

2. Question

   The SI unit of charge is the

   Choices

   1. coulomb
   2. newton
   3. volt

   Correct choice

   coulomb

3. Question

   The ratio of electric to gravitational force between proton and electron is about

   Choices

   1. 9 × 10⁹
   2. 2.4 × 10³⁹
   3. 8.854 × 10⁻¹²

   Correct choice

   2.4 × 10³⁹

4. Question

   k equals

   Choices

   1. 4πε₀
   2. ε₀
   3. 1/(4πε₀)

   Correct choice

   1/(4πε₀)

Explanation