1) The speed of light is approximately 299,792,458 meters per second.

2) International relations encompass the study of relationships between nations, including diplomacy, treaties, and foreign policy. It examines the interactions and dynamics among different countries in the global arena.

3) The first successful mass-produced personal computer, the IBM PC, was introduced in 1981 and played a significant role in popularizing the use of computers in homes and offices.

4) The International Cricket Council (ICC) is the governing body for the sport of cricket and oversees international tournaments and rankings.