Skip to main content
CBT exams on Lena have specific rules and security measures to ensure a fair testing environment. These rules apply to all CBT exams unless your teacher or school has configured them differently.

​
Fullscreen mode

When you start a CBT exam, the browser enters fullscreen mode. This removes distractions and ensures you’re focused on the exam.
  • The exam interface fills your entire screen
  • Browser toolbars, tabs, and other elements are hidden
  • If you exit fullscreen, your exam is automatically submitted
Exiting fullscreen will automatically submit your exam. Stay in fullscreen mode for the entire duration of the exam.

​
Tab-switch policy

The CBT system monitors whether you navigate away from the exam. This includes:
  • Switching to another browser tab
  • Opening a new browser window
  • Clicking on the taskbar or dock
  • Using Alt+Tab or Cmd+Tab to switch applications
  • Minimizing the browser

​
How it works

  1. Each time you switch away from the exam, a counter increments
  2. When you return, you see a warning message showing how many switches you’ve used
  3. If you reach the tab-switch limit set by your teacher, the exam is automatically submitted

​
Tab-switch limits

The limit varies by exam (set by your teacher):
Even accidental tab switches count. Before starting your exam, close all other browser tabs and applications to avoid accidental switches.

​
Auto-submission

Your exam can be automatically submitted (without you clicking Submit) in these situations: When auto-submission happens:
  • All answers you’ve selected up to that point are saved and submitted
  • Your score is calculated based on the answers you provided
  • The submission is marked as auto-submitted in your results
Auto-submitted exams are final. Your teacher can see whether you submitted manually or were auto-submitted.

​
Time limits

Every CBT exam has a time limit set by the teacher (e.g., 30, 60, 90, or 120 minutes).

​
How the timer works

  • The timer starts when you click Begin
  • It counts down continuously — it does not pause if you leave the page or lose internet
  • The remaining time is always visible on screen
  • When time runs out, the exam is auto-submitted

​
Exam window vs duration

These are two different things: You can start the exam at any point during the window, and you’ll get the full duration from that point.

​
Allowed attempts

Your teacher sets how many times you can take the exam: If multiple attempts are allowed, your best or most recent score is typically used (depends on teacher settings).

​
Preparing for your exam

Follow these tips to avoid issues during your CBT exam:
1

Close everything else

Close all other browser tabs, applications, and background programs. This prevents accidental tab switches. Your desktop should show only your browser.
2

Use a supported browser

Use the latest version of Chrome, Firefox, or Edge. Safari may have limited fullscreen support. Verify your browser is up to date in its settings.
3

Check your internet

Make sure you have a stable internet connection. If possible, use a wired connection instead of Wi-Fi. Test by loading a web page to confirm connectivity.
4

Disable notifications

Turn off system notifications, pop-ups, and alerts that might pull you away from the exam. Your notification center should be empty or in Do Not Disturb mode.
5

Disable browser extensions

Some extensions can interfere with fullscreen mode or trigger tab-switch detection. Disable them before the exam. You can re-enable them afterward.
6

Plug in your charger

Don’t let your laptop die during the exam. Plug in your charger before starting. Confirm your battery is charging.