Q) light travels at a speed of 3.00*10^8 ms ^-1. light from the star sirius takes 8.65 years to reach the earth. what is the distance of sirius from the earth in kilometres?
Q) The guns were at the battle of the english fleet against the Dutch off the kent coast, a distance of between 110 and 120 km away. The speed of sound in air is 344ms^-1. How long did it take the sound of the gunfire to reach London?