One light year is equal to

A light year is a unit of astronomical distance representing the total distance light travels in a vacuum during one Julian year [c1][t2]. Light travels at a constant speed of approximately 300,000 km/s or 3 x 10^8 m/s [c1][c3]. To calculate the distance in meters, this speed is multiplied by the number of seconds in a year (approximately 3.15 x 10^7 seconds) [t8]. This calculation yields a value of approximately 9.46 x 10^15 meters [t1][t6]. While some sources express this as 9.46 x 10^12 kilometers [c1], converting kilometers to meters (multiplying by 10^3) confirms the value as 9.46 x 10^15 m [t3][t9]. Therefore, option 2 is the correct scientific representation of one light year in meters.

Sources

1. [1] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 2: The Origin and Evolution of the Earth > The Star Formation > p. 14
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > What you have learnt > p. 159