Question

Why was the kilogram redefined in 2019, and how is it measured now?

Options

• old object was too heavy; now it's based on light

• old object could change; now it's based on electric force

• The cylinder broke; now it's based on temperature

• old method was slow; now it's based on sound waves

Answer 1

old object could change; now it's based on electric force
Reason:

The old kilogram was a metal block that could change over time. The new one uses the Planck constant and electric force, making it more accurate and stable.