Application.Loadlevel taking time to load scene

I’m using Vuforia ImageTarget. I have button on change the scene. When i click the button, it taking 5 to 10sec to load the next scene. Even i used AboutScreenmanager.cs script start button also. It taking time to load my second scene. Why? = startbtnstyle;
if(GUILayout.Button("Start", startbtnstyle)){

it depend on how many assets you load with your scene. do you have a lot of models and audio loading with the scene?