What is the value of the elementary charge?

• A. 1.602 × 10^−19 C
• B. 1.602 × 10^−18 C
• C. 1.602 × 10^−20 C
• D. 1.602 × 10^−17 C

Answer: (A)

The elementary charge is a fundamental physical constant that represents the smallest unit of electric charge, which is carried by a single proton or is equal in magnitude but opposite in sign to the charge of a single electron. Its accurate value is approximately 1.602 × 10^−19 coulombs (C). This value is critical in various fields of physics and engineering, especially when dealing with atomic and subatomic particles.

Protons and electrons, the building blocks of atoms, have a charge of ±1.602 × 10^−19 C. Understanding this value is essential for calculations in electrostatics, circuit analysis, and many areas of electronics and materials science. Recognizing the significance of the elementary charge aids in the comprehension of electric force, potential, and capacitance in theoretical and practical applications.