Final answer:
Using Coulomb's law, the magnitude of the electrostatic force between two point charges of +3.0 x 10^-7 C and +4.0 x 10^-7 C, separated by 2.0 x 10^-2 m, is calculated to be 3.0 x 10^-1 N.
Step-by-step explanation:
The magnitude of the electrostatic force between two point charges can be determined using Coulomb's law, which states that the force (F) between two charges (q1 and q2) at a distance (r) apart in a vacuum is given by F = k * |q1 * q2| / r^2, where k is Coulomb's constant (approximately 8.9875 × 10^9 N m^2/C^2). Plugging in the given values of the point charges, +3.0 × 10^-7 C and +4.0 × 10^-7 C, and their separation of 2.0 × 10^-2 m, we calculate the electrostatic force.
F = (8.9875 × 10^9) * ((3.0 × 10^-7) * (4.0 × 10^-7)) / (2.0 × 10^-2)^2
F = (8.9875 × 10^9) * (12 × 10^-14) / (4 × 10^-4)
F = (8.9875 × 10^9) * (12 × 10^-14) / (4 × 10^-4)
F = (8.9875 × 10^9) * (3 × 10^-10)
F = 2.69625 × 10^-1 N
After adjusting for significant figures, the correct answer is b) 3.0 × 10^-1 N.