Question:Which components can be injected as a dependency in AngularJS? 

AngularJS provides a supreme Dependency Injection mechanism. It provides following core components which can be injected into each other as dependencies.

value
factory
service
provider
constant

Question:How to make an ajax call using Angular JS? 

AngularJS provides $http control which works as a service to make ajax call to read data from the server. The server makes a database call to get the desired records. AngularJS needs data in JSON format. Once the data is ready, $http can be used to get the data from server in the following manner:
function studentController($scope,$http) {
   var url = "data.txt";
   $http.get(url).success( function(response) {
      $scope.students = response; 
   });
}

Question:What is use of $routeProvider in AngularJS? 

$routeProvider is the key service which set the configuration of urls, maps them with the corresponding html page or ng-template, and attaches a controller with the same.

Question:How to validate data in AngularJS? 

AngularJS enriches form filling and validation. We can use $dirty and $invalid flags to do the validations in seamless way. Use novalidate with a form declaration to disable any browser specific validation.

Following can be used to track error.

$dirty − states that value has been changed.

$invalid − states that value entered is invalid.

$error − states the exact error.