Riya, a Class 12 student in Lucknow, finished her Physics file in one night. The diagrams were perfect. The observations were copied from a friend. The external examiner asked, “Why did your screw gauge reading have a zero error?” Riya froze.
This one moment is what the CBSE practical exam 2027 is really about. Marks are easy to lose here, and just as easy to collect.
CBSE Practical Exam 2027: Dates at a Glance
CBSE issued the practical circular on 5 November 2026, and the board date sheet followed on 6 November. Both documents are available on cbse.gov.in and cbseacademic.nic.in.
Who | Practical and internal assessment window |
Winter-bound schools | 9 November to 19 December 2026 |
All other schools | 1 January to 13 February 2027 |
Theory exams begin | 16 February 2027 |
Class 10 theory ends | 9 March 2027 |
Class 12 theory ends | 9 April 2027 |
Your own school fixes the exact day for your batch.
Do practical marks really matter? Yes. Schools upload practical, project and internal assessment marks to CBSE along with the theory marks. Once uploaded, they are part of your final result.
Marks Split: What Is Actually at Stake
Class | Subject | Theory | Practical, project or internal |
10 | Most subjects, including Maths | 80 | 20 internal assessment |
10 | Computer Applications | 50 | 50 |
10 | Home Science | 70 | 30 |
12 | Physics, Chemistry, Biology | 70 | 30 |
12 | Computer Science, Geography, Psychology | 70 | 30 |
12 | Economics, Business Studies, Accountancy | 80 | 20 project |
12 | Mathematics | 80 | 20 internal |
Class 10 gets no outside examiner. Class 12 subjects follow a subject-wise table in the circular, and Class 12 Science practicals carry an outside examiner. Check your own subject in the circular on cbseacademic.nic.in.
Viva Questions: What Examiners Really Ask
Examiners rarely hunt for tricky questions. They check whether the person who wrote the file also did the experiment. Short, honest answers score well.
Physics viva questions
What is least count? The smallest reading an instrument can measure. A vernier caliper usually reads 0.01 cm, and a screw gauge usually reads 0.01 mm.
What is zero error? The reading shown when the jaws are closed. It must be corrected in the final answer.
Why is a meter bridge balanced near the middle? Readings near the centre give the least percentage error.
Why touch the jockey lightly? Pressing hard can scrape the wire and change its resistance.
Chemistry viva questions
Why rinse a burette with the solution but not the conical flask? The burette must not dilute its solution. A wet conical flask does no harm because the moles of solute stay the same.
Why does KMnO4 need no indicator? It is a self-indicator. One extra drop turns the solution light pink.
Why use dilute sulphuric acid in this titration? Hydrochloric acid and nitric acid interfere with the reaction.
Biology viva questions
Why stain an onion peel with safranin? The stain makes the cell wall and nucleus easier to see.
Why put a coverslip at an angle? It keeps air bubbles out.
Computer Science viva questions
Difference between DDL and DML? DDL changes structure, like CREATE and ALTER. DML changes data, like INSERT and UPDATE.
What is a primary key? A column that identifies each row uniquely and cannot be empty.
If a question stumps you, say “I did not note that, but I think it is because…” and reason it out loud. Honest thinking beats silence every time.
Basic Viva Questions for Every Stream (Arts, Science and Commerce)
Some questions show up in almost every CBSE practical exam 2027 viva, whatever the subject. Examiners use them to check whether the student did the work. Prepare short, honest answers to these first.
Questions asked in all streams
What is the aim of your experiment or project?
Why did you choose this topic?
Explain the procedure in your own words.
What precautions did you take?
What was your result or conclusion?
Where could errors have crept in?
Which part of the file did you enjoy most, and why?
What would you change if you did it again?
Can you walk me through any one page of your file?
How to answer “Did you do this yourself?”
Say yes, then prove it with one small detail. “Yes, I collected the readings over two days, and the second set had a small error, so I repeated it.” Details like that sound real because they are.
Project File Tips: Step by Step
Class 12 commerce students and Class 10 students submit files or projects for their 20 marks. Follow this order and nothing gets missed.
Start with the basics. Cover page, certificate, acknowledgement and index come first, signed where required.
Write the aim in one clear line. Examiners read this line first.
Record real observations. Use your own readings, even when they look messy. Copied data is easy to spot.
Draw neat diagrams with labels. Use a pencil for the diagram and ink for the text.
Finish with a short conclusion and precautions. Two or three sentences each is enough.
Get every experiment signed before the exam. An unsigned page can cost marks.
Keep a phone photo of every page. Files do get lost between school and home.
Common Mistakes Students Make
Copying the entire project from a website or a senior’s file.
Swapping data between experiments to “fix” an answer.
Leaving out units in calculations.
Writing the file on the final weekend.
Skipping the viva revision because “the file is done.”
Is it fine to take help from a senior’s file? Using it as a reference is fine. Submitting it is risky because an examiner can ask you to explain any page.
Smart Revision Plan Before January
Week | Task |
Week 1 | Complete all pending experiments and get signatures |
Week 2 | Rewrite messy pages and finish diagrams |
Week 3 | Revise the aim, procedure and result of each experiment aloud |
Week 4 | Practise ten viva questions per subject with a friend |
Twenty minutes a day is enough when you start now.
Quick Answers Students Keep Asking
Can a student reappear for practicals if absent?
Schools follow CBSE’s rules on this. Speak to your teacher at once and keep a medical or written reason ready. Note: there is no provision to improve practical marks later. Improvement attempts are strictly for theory papers, as confirmed by CBSE Controller of Examinations Sanyam Bharadwaj.
Does the practical file get marks on its own?
Marks usually cover the experiments, the file, the viva and attendance, so every part counts.
Where will the official circular be?
Check cbse.gov.in and cbseacademic.nic.in, and ask your school for the practical schedule.
Key Takeaways
The CBSE practical exam 2027 runs from 1 January to 13 February 2027 for most schools.
Winter-bound schools hold practicals from 9 November to 19 December 2026.
Practical marks are awarded in school, so they are the steadiest marks in the result.
A neat file is only half the job. The viva proves the work is yours.
Start revising now and keep a photo backup of the file.
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