a) How long does it take for sunlight to reach Pluto?
b) How long does it take for light to reach you from a lightning stroke 9.5 km away?
c) How long does it take for a microwave radar signal to travel from Earth to the Moon and back?
d) The distance to a star is about 7.10 1018 m. If this star were to burn out today, in how many years would we see it disappear?
e) How long does it take for a radio wave to travel once around the Earth in a great circle, close to the planet's surface?