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In an oral test you cannot cross anything out: the examiner hears your first attempt, then asks a follow-up. So prepare the way you will be tested, out loud, with short answers and a plan for when you are stuck.
What does a school viva actually test?
A viva checks whether you understand what you did and wrote, not just whether you copied it into a record book. In CBSE Class XI physics for 2026-27, the 'viva on experiments, activities and project' carries 5 of the 30 practical marks, according to the CBSE physics curriculum for 2026-27.
Expect three kinds of question: what something is, why you did a step, and what would change if something were different. For nerves and body language, see our guide on how to speak confidently in a viva.
Why should you practise answers out loud?
Rereading notes feels productive but can fool you. In a 2006 study by Henry Roediger and Jeffrey Karpicke, students who practised recalling a prose passage remembered more of it two days and one week later than students who restudied it, even though restudying made them feel more confident.
Across eight experiments, Colin MacLeod and colleagues (2010) found that words said aloud during study were remembered better than words read silently. The benefit appeared when only some items were spoken, which suggests speaking makes them stand out, so say aloud the definitions you most need rather than the whole chapter. Our post on whether reading aloud helps you remember goes further.
Explaining builds understanding, not only memory. In a 1994 study by Michelene Chi and colleagues, eighth-graders prompted to explain each line of a circulatory-system text to themselves gained more from pretest to posttest than those who read it twice.
How do you build two-line definitions and examples?
For every key term or experiment, write a two-line answer and one example. Line one says what it is. Line two says why it matters or how it is measured. The example shows you can use it.
Two worked examples from the Class XI practical list:
Least count. The least count is the smallest reading an instrument can measure. For vernier callipers, it equals one main-scale division minus one vernier-scale division. Example: if 10 vernier divisions match 9 main-scale divisions of 1 mm, the least count is 1 mm minus 0.9 mm, which is 0.1 mm.
Surface tension. Surface tension is the force per unit length acting on a line drawn in a liquid surface, which makes the surface behave like a stretched skin. Its SI unit is newton per metre. Example: water rises in a narrow glass capillary tube, and in the practical the height it rises lets you calculate surface tension.
Stop at two lines; if the examiner wants more, they will ask. If you cannot get a term down to two lines, that usually points to a gap in the idea itself. The Fermi Concept Library gives every concept in physics, chemistry, biology and mathematics its own lesson, so you can fix the idea before you shorten it.
A five-day plan before your oral test
Work from your record book and the CBSE syllabus or your school's list.
Day 1: List the terms and experiments. Write a two-line answer and one example for each.
Day 2: Cover your notes and say each answer aloud. Tick the ones you got right and mark the rest.
Day 3: Ask a parent, sibling or friend to read your cards in random order. They only check your answer against the card.
Day 4: Climb the follow-up ladder for every experiment, then add its precautions.
Day 5: Run a ten-minute mock viva standing up, including two questions you have not seen. Practise the script below.
Parents, on day 3 ask, wait, and say 'try again' instead of giving the answer. For a practice partner who can also explain, Fermi's AI tutor decides whether to explain, ask or show, and checks understanding as it goes, so you practise being questioned rather than only reading.
What should you say when you don't know the answer?
Don't bluff: a bluff often invites a harder follow-up. Use this script instead:
Buy a moment: 'Could you repeat the question, please?' or 'Let me think for a second.'
Reason from what you know: 'I'm not certain, but I think it depends on the length of the wire, because...'
Be honest if you are still stuck: 'I don't know that one yet. What I do know is...' and give a related fact.
Reset: one slow breath, then treat the next question as a fresh start.
If your mind goes blank, try the routine in our post on what to do when you blank out in an exam.
Some nervousness before a viva is normal. If worry is stopping you from sleeping, eating or going to school, talk to a parent, teacher or school counsellor, or call Tele MANAS, India's national tele-mental health helpline, on 14416.
Start tonight: pick five terms, write two lines and one example for each, and say them out loud once.
