Question

List the differences of Doppler effect betweem mechanical waves and electromagnetic waves.What is proper time in relativity?

Answer 1

1. mechanical waves need a medium for its transmission where as electro magnetic waves have no medium to travel.

2. mechanical waves does not travel through vaccum whereas electro magnetic waves travel through vacuum.

3. mechanical waves are caused by amplitude whereas electro magnetic waves are caused because of varying magnetic and electric fileds.

4. mechanical waves are considered as periodic disturbance whereas electromagnetic waves are considered as disturbance.

in relativity proper time is nothing but the time measured by a clock following that line that means the proper time interval between two events on a world line is the change in proper time.