The speed of ight deends

Complete the anology: The speed of sound : ……. : : The speed of light : …….

The ratio of speed of light in vaccum to the speed of light medium is __________ .

The speed of boat upstream and speed of boat downstream are 7 km/h and 13 km/h, respectively. Find the speed of stream and speed of boat in still water.

The speed of a boatin still water is 9 km/hr and the speed of stream is 3 km/hr. The difference between the upstream speed and downstream speed will be: