Here Is How to Time Your Google Forms Quizzes | TIC & Educación | Scoop.it
Quilgo is an excellent tool that allows you to time quizzes created on Google Forms. You can specify the duration of the quiz and choose whether or not  you want to force forms to close when the time is over. Keep in mind that if you choose to have forms automatically close after the time is over students will have to submit their forms within the allotted timeframe or else they can not. When you do not activate this option you will be able to see how long students spend overtime working on their quiz.