Write any two applications of interference.

Hint: In physics the interference can be defined as the phenomenon in which two waves superpose on each other to form a single resultant wave of lower, greater or same amplitude. Understand this definition and try to analyze the applications of this interference.

Complete answer:
 There are various applications of the interference which is defined as the phenomenon of which two or more coherent waves will superimpose on each other and form a single resultant wave which will have greater or lower or of the same amplitude. The interference can be constructive or destructive which is resultant from the interaction of the waves which are coherent with each other
 Some of the applications of the interference are:
1.Optical testing
2.Space applications
In optical testing, interference is used in testing surface quality like: flat surface, spherical surface, roughness of surface etc.
Whereas in space applications include Radio astronomy, measuring light intensity, in retrieving images from the telescopes.

Note:
Two sources are said to be coherent if both the waves came from the same source or because they have the same or nearly the same frequency. This effect of interference can be observed with all types of waves, for example light waves, matter waves, radio waves or surface water waves etc. the resulting images or graphs are called interferograms.