Two tiny grains of sand having charges of 4.0 μC and -4.0 μC are situated along the x-axis at x₁ = 2.0 m and x₂ = -2.0 m.What is electric potential energy of the system of these grains assuming that at infinity the energy of the system is zero? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

Question

Quizplus · Accepted Answer

The electric potential energy (U) of a system of two charges is given by the formula U = kq1q2/r, where k is Coulomb's constant (9.0 × 10^9 N∙m^2/C^2), q1 and q2 are the charges, and r is the distance between them. Here, q1 = 4.0 μC = 4.0 × 10^-6 C, q2 = -4.0 μC = -4.0 × 10^-6 C, and r = 4.0 m (the distance between -2.0 m and 2.0 m). Plugging these values into the formula gives U = (9.0 × 10^9)(4.0 × 10^-6)(-4.0 × 10^-6) / 4.0 = -36 × 10^-3 J = -36 mJ.

Two Tiny Grains of Sand Having Charges of 4