The CBT app
Lena has a dedicated CBT app at cbt.lena.africa — separate from the Student and Teacher apps. This app is purpose-built for taking exams with:- Fullscreen mode to minimize distractions
- Tab-switch detection to maintain exam integrity
- Real-time timer synced with the server
- Auto-save so answers aren’t lost if connectivity drops
- Auto-submission when time expires or rules are violated
Who does what
Students
- Log in to the CBT app - Find and start assigned exams - Answer multiple-choice questions - Submit when done (or get auto-submitted) - View results when published
Teachers
- Create exams in the Teacher App - Add multiple-choice questions - Configure exam settings and rules - Assign students to the exam - Monitor submissions and publish results
School Admins
- Approve exams before they go live - Manage which classes are assigned
- Assign proctors to monitor exams - View submissions across all exams - Preview questions for quality control
The exam lifecycle
Teacher creates the exam
The teacher creates a new CBT exam in the Teacher App, adds
multiple-choice questions, configures settings (duration, tab-switch
limit, etc.), and assigns students. The exam is saved as a draft.
Admin reviews and approves (optional)
Depending on the school’s workflow, a school admin may need to review
and approve the exam before it becomes available to students. The exam
status changes to approved.
Exam is published
The teacher publishes the exam. It becomes available to assigned
students during the exam window (between the start and end times). The
exam appears on student dashboards.
Students take the exam
Students log in to the CBT app, find the exam on their dashboard, and
begin. The browser enters fullscreen mode, the timer starts, and tab
switches are monitored.
Exam is submitted
Students submit manually when they’re done, or the exam is
auto-submitted when time expires or the tab-switch limit is exceeded.
The submission is recorded with score and metadata.
Security features
CBT exams include several security measures to maintain exam integrity:| Feature | Description |
|---|---|
| Fullscreen mode | The exam fills the entire screen, hiding browser UI and other apps |
| Tab-switch detection | The system detects when you navigate away from the exam |
| Tab-switch limit | Teachers set a maximum number of tab switches before auto-submission |
| Server-side timer | The countdown runs on the server — it can’t be paused or manipulated |
| Fullscreen enforcement | Exiting fullscreen immediately auto-submits the exam |
| Developer tools detection | Opening browser dev tools triggers a countdown and then auto-submission |
| Auto-submission | Exams are automatically submitted when time expires or rules are violated |
| Submission tracking | Teachers and admins can see whether each exam was submitted manually or auto-submitted |
| Tab-switch count | The number of tab switches is recorded and visible to teachers |
Guides by role
Taking an Exam
For Students — How to log in, find your exam, take it, and submit
Viewing Your Results
For Students — How to check your scores and review your answers
Creating an Exam
For Teachers — How to create exams, add questions, and publish
Managing Exam Results
For Teachers — How to monitor submissions and publish results
Admin CBT Oversight
For School Admins — How to approve exams, assign proctors, and
oversee CBT
Exam Rules & Policies
For Everyone — Fullscreen, tab-switch policies, auto-submission, and
time limits
CBT Troubleshooting
For Everyone — Solutions to common CBT issues