The speed of light in a vacuum commonly denoted c, is a universal physical constant important in many areas of physics. Its exact value is 299,792,458 metres per second (approximately 300,000 km/s (186,000 mi/s). It is exactly because by international agreement a meter is defined as the length of the path traveled by light in vacuum during a time interval of 1/299792458 second.
1 Light Speed = 2,99,792 Kilometer Per Second
Time need to Come Light from Sun to Earth :
Source: Wikipedia
https://en.wikipedia.org/wiki/Speed_of_light