In the International System of Units (SI), what is the base unit for mass?

• A. pound (lb)
• B. kilogram (kg)
• C. newton (N)
• D. gram (g)

Answer: (B)

Verified step by step guidance

1. Understand that the International System of Units (SI) defines seven base units, each corresponding to a fundamental physical quantity.
2. Recall that mass is one of these fundamental quantities, and the SI base unit for mass is specifically designated.
3. Note that while the gram (g) is a unit of mass, it is not the SI base unit; it is derived from the kilogram.
4. Recognize that the kilogram (kg) is the SI base unit for mass, defined by a fixed numerical value of the Planck constant.
5. Conclude that among the options given, the kilogram (kg) is the correct SI base unit for mass.