How to Prepare for Viva and Practical Exams - Tips for Class 10 and 12 Students

Practical exams and viva voce carry 20-30 marks in subjects like Science, Computer Science, and Physical Education for both Class 10 and Class 12 CBSE boards. Many students lose marks not because they do not know the experiments, but because they do not know how to present their knowledge confidently during the viva.

Here is a complete guide to scoring well in both practicals and viva.

Understanding the Marks Split

Class 10 Science Practicals (20 marks):

• Lab work during the year: 5 marks
• Practical examination: 8 marks
• Viva voce: 5 marks
• Internal assessment: 2 marks

Class 12 Physics Practicals (30 marks):

• Two experiments (8+8): 16 marks
• Practical record/project report: 6 marks
• Viva on experiments/activities: 8 marks

Class 12 Chemistry Practicals (30 marks):

• Volumetric analysis: 8 marks
• Salt analysis: 8 marks
• Content-based experiment: 6 marks
• Class record and viva: 8 marks

Class 12 Biology Practicals (30 marks):

• One major experiment: 5 marks
• One minor experiment: 4 marks
• Slide preparation: 5 marks
• Spotting: 7 marks
• Practical record + viva: 9 marks

How to Prepare for Practical Exams

Start early, not the night before:

• Attend all lab sessions during the year
• Do each experiment at least 2-3 times
• Maintain a neat practical notebook throughout the year

For Physics practicals:

• Know the principle behind every experiment (this is what viva questions test)
• Practice reading Vernier calipers, screw gauges, and galvanometer scales
• Understand circuit diagrams and be able to set them up independently
• Practice drawing graphs and calculating results
• Know the least count of every instrument you use

For Chemistry practicals:

• Practice volumetric analysis until your readings are consistent
• Memorize the systematic procedure for salt analysis (preliminary tests, group analysis)
• Know the colors and precipitates formed in different reactions
• Practice writing balanced equations for all reactions you perform
• Maintain a clean apparatus and follow proper lab procedures

For Biology practicals:

• Practice slide preparation (especially T.S. of stems, leaf cross-sections)
• Know how to use a microscope properly (adjusting focus, changing objectives)
• Study all spotting specimens thoroughly - know their names, classification, and key features
• Practice drawing labeled diagrams of specimens
• Understand the logic behind each experiment, not just the procedure

Common Viva Questions and How to Answer Them

Viva questions follow predictable patterns. Here are the most commonly asked ones:

Physics Viva - Common Questions:

• What is the principle of this experiment?
• Why do we take multiple readings?
• What are the sources of error in this experiment?
• What is the least count of the instrument? How do you calculate it?
• What would happen if you change (a specific variable)?
• What precautions should be taken during this experiment?
• What is the difference between accuracy and precision?
• Why do we use a galvanometer instead of an ammeter in certain circuits?

Chemistry Viva - Common Questions:

• What is the indicator used and why?
• Why is the solution heated/cooled at a specific step?
• What is the role of dilute HCl vs concentrated HCl in salt analysis?
• Write the balanced equation for the reaction you just performed
• What happens if you add excess reagent?
• Why do we perform a confirmatory test after the preliminary test?
• What is the normality of the solution you prepared?
• Name the type of reaction taking place

Biology Viva - Common Questions:

• Identify this specimen and state its classification
• What is the function of the part you have labeled?
• Why is this stain used for this particular slide?
• What are the differences between the two specimens shown?
• How would you distinguish between a monocot and dicot stem under the microscope?
• What is the ecological significance of this organism?
• Explain the principle behind this experiment

Tips for the Viva Itself

The viva is essentially a short oral exam. How you present yourself matters:

Before the viva:

• Revise all experiments and their principles the night before
• Review your practical notebook
• Be familiar with all instruments and their uses
• Prepare for questions beyond just the experiment (related theory questions)

During the viva:

1. Listen to the full question. Do not start answering before the examiner finishes
2. Take a moment to think. A 3-second pause to organize your thoughts is perfectly fine
3. Speak clearly and confidently. Even if you are unsure, speak with a steady voice
4. Start with the basic answer, then add details. Examiners appreciate structured responses
5. If you do not know the answer, say so honestly. "I am not sure about this, but I think..." is better than silence or making up wrong information
6. Make eye contact with the examiner. It shows confidence
7. Keep answers concise. Do not ramble. Answer the question asked, not everything you know about the topic
8. Use correct scientific terminology. Say "precipitation reaction" not "the thing where white stuff forms"

Practical Exam Day Checklist

What to carry:

• Practical notebook (clean, complete, and signed by the teacher)
• Stationery (pen, pencil, ruler, eraser, calculator if allowed)
• Any specific materials your teacher has asked you to bring
• Your school ID card

What to do in the exam:

• Read the experiment instructions carefully before starting
• Set up your apparatus neatly
• Take readings carefully and record them immediately
• If something goes wrong, ask the examiner for guidance rather than guessing
• Draw clear, labeled diagrams in your answer sheet
• Write calculations step by step
• Double-check all values before writing the final result

Subject-Specific Last-Minute Tips

Physics:

• Revise the formula for each experiment
• Practice connecting circuits once more
• Review all graph types (V-I characteristic, lens formula graphs)
• Know how to calculate percentage error

Chemistry:

• Revise the colors of all precipitates and solutions
• Practice the sequence of salt analysis (cation and anion tests)
• Review titration end-point indicators and color changes
• Know the molarity and normality calculations

Biology:

• Go through all spotting specimens with labeled diagrams
• Revise slide preparation steps for each type
• Practice identifying specimens from photographs
• Review the differences between similar-looking specimens

Common Mistakes That Cost Marks

1. Not reading the question paper properly and doing the wrong experiment
2. Messy practical record. A well-maintained notebook earns you marks even before the exam starts
3. Not explaining while performing. Some examiners observe you during the experiment. Explain what you are doing and why
4. Panicking during the viva. Staying calm and giving partial answers is better than freezing
5. Ignoring safety precautions. Not wearing a lab coat, handling chemicals carelessly, or not following proper procedures can lose you marks
6. Submitting incomplete observation tables. Fill in every column

How to Handle Difficult Viva Questions

Sometimes examiners ask questions beyond the syllabus to test depth. If this happens:

• Relate the question to something you do know
• Give a logical answer based on the principles you have learned
• It is okay to say, "This is beyond what we covered, but based on [concept], I think..."
• Never argue with the examiner, even if you believe your answer is correct

For revising the theory behind your experiments quickly, Padhaao can explain the principles and answer your doubts on any practical topic. This is especially useful the night before your practical exam when you need quick, clear explanations.

Practical exams are among the easiest marks to score if you prepare properly. Know your experiments, understand the theory behind them, and walk in with confidence. Those 20-30 marks are waiting for you.