Fathometer is used to measure

In the following is not an example of refraction of light.

Ice is packed in sawdust because___

When a body falls from an aeroplane, there is increase in its 

When a stone is thrown in the calm water of a pond the waves produced on the surface of water in the pond are

The time period of a pendulum – 

What will remain unchanged if the quantity of the commodity changes?

What is the minimum unit of length?