quiz lock after time ends

can I make a timed quiz that locks after time ends? 

You can use the Global Countdown widget: https://widgets.jotform.com/widget/global_countdown, to prevent the form from being submitted, or submit the form right away as soon as the time has run out.

https://www.jotform.com/help/252-How-to-Add-a-Widget-to-your-Form 

Open a new thread if you need anything else, we will be glad to assist you.