Question

Which of the following cannot be used as a standard of measurement?

• A. True
• B. False
• C. Speed of light
• D. Both B and C.

Answer 1

Answer: (B)

Human foot

The length of a foot varies from person to person. It also varies with age for the same person. Due to this, a foot cannot be used as a standard of measurement. But the speed of light is constant everywhere. Standards of measurements are constant irrespective of where they are measured i.e., 1cm measured anywhere in the world, at any point in time will be of the exact same length. Hence, a human foot cannot be used as a standard of measurement.