What is the difference between mass and weight. Which changes

Weight depends on gravity whereas mass doesn't depend on the gravity.

Explanation:

Mass:                                    

1. Mass is the amount of matter present in an object.

2. Wherever we go in the universe, the mass will never get changed

3. It is measured in Kilograms (kg)

Weight:

1. Weight is the amount of the downward force that is the gravity  acts on an object.    

2. Weight  will change from one place to another place.

3. It is measured in Newtons (N).      

low freq = 100 mhz

low wavelength =101.7m

length = 3x10^8/freq