A certain particle carries 2.5 × 10⁻¹⁸ C of static electric charge. Calculate the number of electrons present in it.
Solution:
One electron has charge 1.602 × 10⁻¹⁹ C. The number of electrons present in the charged particle is 2.5 × 10⁻¹⁸ / 1.602 × 10⁻¹⁹ = 1.56 × 10¹. Thus, the number of electrons present in the charged particle is = 1.56 × 10¹.