Is the long sound of a vowls represents with macron?

Yes, you are correct! A macron is a horizontal line placed over a vowel to indicate that it is pronounced long.

Here are some examples:

* ā as in "fate"

* ē as in "tree"

* ī as in "time"

* ō as in "go"

* ū as in "flute"

This notation is commonly used in dictionaries, linguistics, and language learning materials.