Final answer:
The number of excess electrons required to produce a charge of -1.0 C is 6.25 × 10¹⁸. So, option A is correct.
Step-by-step explanation:
To determine the number of excess electrons necessary to produce a charge of -1.0 coulomb (C), we use the fundamental charge of an electron, which is approximately -1.602 x 10⁻¹⁹ C. By dividing the total charge by the charge per electron, we can calculate the number of electrons.
So, the correct option is a. 6.25 × 10¹⁸ because this value, when multiplied by the charge of a single electron, equals -1.0 C. In mathematical terms, (6.25 × 10¹⁸) × (-1.602 x 10⁻¹⁹ C) equals approximately -1.0 C, which confirms our calculation. The fundamental principles of electric charge are based on the knowledge that the charge is quantized and electrons carry the base unit of charge of -1.6 × 10⁻¹⁹ C. However, there appears to be a duplicate option (b) in the provided choices, so the correct answer is (a), and none of the above options exactly matches the calculated value.