Which of the following statements about electric charge is true?

• A. Electric charge can be created or destroyed in an isolated system.
• B. Electric charge is quantized, meaning it always exists in integer multiples of the elementary charge $e$.
• C. The SI unit of electric charge is the volt.
• D. Protons and electrons have the same sign of electric charge.

Answer: (B)

Verified step by step guidance

1. Understand the concept of electric charge: Electric charge is a fundamental property of matter that causes it to experience a force when placed in an electromagnetic field.
2. Recall the principle of conservation of charge: Electric charge cannot be created or destroyed in an isolated system; it can only be transferred from one object to another.
3. Recognize that electric charge is quantized: This means charge exists in discrete amounts, specifically integer multiples of the elementary charge \(e\), where \(e \approx 1.6 \times 10^{-19}\) coulombs.
4. Identify the correct SI unit for electric charge: The SI unit of electric charge is the coulomb (C), not the volt. The volt is the unit of electric potential difference.
5. Note the sign of charges on protons and electrons: Protons have a positive charge, while electrons have a negative charge, so they do not have the same sign.