Light Year Unit Analysis

A light-year is fundamentally a unit of distance. It measures the distance light travels in a vacuum over one year.

Option Analysis

• Second: This is a unit of time.
• Kilogram (kg): This is a unit of mass.
• Square metre: This is a unit of area, which is distance squared (\(m^2\)).
• Angstrom: This is a unit of distance, often used for atomic and molecular scales (\(1 \text{ \unicode{x212B}} = 10^{-10} \text{ m}\)).

Conclusion

The question asks for a unit that measures the same quantity as a light-year. Since a light-year measures distance, and the Angstrom is also a unit of distance, it is the correct choice among the given options.