Difference between Group and phase velocity

[ajeet mishra]

Hi! I am having problem in understanding the difference between phase and group velocity clearly. In my textbook phase velocity is given by ω/κ while group velocity is by dω/dκ. What is the difference between these two terms?
Thank you!

 

[blue_leaf77]

There are some interesting animations on this subject:

 

[ajeet mishra]

thanks I have got it