Use jQuery to detect if radio button is selected.

I'm creating an online test that returns all the question text,image associated it available and a series of questions. I had a need to check if a current questions radio buttons is selected, if not force the user to select. I was returning all the generated test questions dynamically from ajax and hiding every question but the 1st. 
Update 4/8/15
In creating the radio's dynamiclly I had the add the attr checked="" for every one. Otherwise the below code will only work for the 1st selection that you do.
Each test question I attached a data attribute called data-count=current_count and also attached current_count to the class of the radio inputs as well. for example { class="answerRadio'+current_count+'" } make sure your using the class attribute and not ID because jQuery and Css treat ID as a unique element. In doing this I made sure that each radio group and question was unique.
The following function finds the current .answerRadio and makes sure that it's selected, if so it will increase the current_count by 1, find the value of the radio button selected and get my current question ID. Else it will prepend an error message.
$(document).on('click',".submitAnswer" ,function(){
     if ($(".answerRadio"+current_question).is(':checked')) {
     var UA = $("input[name=answers"+current_question+"]:checked").val();
     console.log('UA = '+UA);
     var qID = $("##submitAnswer"+current_question).data("qid");
     $('##listOfQuestions').parent().prepend('<div class="alert alert-info alert-dismissible" role="alert" style="margin:0 10px 10px" ><strong>Heads Up!</strong><br/>Please select an answer.</div>');
If the follow if statement is true I send the current_question,qID and answer into a function that will one remove any error fields if present { $("div").remove(".alert-dismissible"); } then do an ajax post to my server side page/componet.
stay frosty