Html5 <nav> tag use

Question

Can we use <nav> tag with the rest of <header> tag in HTML 5?

Answer 1

The HTML5 spec has an example where a nav element is a child of a header element, so yes.

Answer 2

The <nav> tag can be used to wrap any navigational links. Whether those links are in the header or the footer or otherwise in the page, if they are a distinct section for navigation, those links can be grouped within a <nav> tag.

See http://www.w3schools.com/html5/tag_nav.asp