How can I get the value of the checked radio button when submitting a form using angularjs?

How can I get the value of the checked radio button when submitting a form
using angularjs?

References

Reference NO 1

http://stackoverflow.com/questions/15166270/how-can-i-get-the-value-of-the-checked-radio-button-when-submitting-a-form-using

Reference NO 2

http://stackoverflow.com/questions/16776919/how-to-make-selecting-a-radio-button-required-before-submitting

Reference NO 3

http://docs.angularjs.org/api/ng.directive:input.radio

Reference NO 4

http://odetocode.com/blogs/scott/archive/2013/06/25/radio-buttons-with-angularjs.aspx

Reference NO 5

https://github.com/angular/angular.js/issues/271

Reference NO 6

http://docs-angularjs-org-dev.appspot.com/api/ng.directive:input.radio

Reference NO 7

http://viralpatel.net/blogs/angularjs-controller-tutorial/

Reference NO 8

http://www.slideshare.net/EyalV/forms-in-angularjs