The Class 10 Science Board exams are a crucial milestone that students have to move through. The viva component is usually the hardest part of the examination, especially because it checks on theoretical and practical understanding and applications. Knowing the most commonly asked viva questions can give you an edge, helping you prepare effectively and answer confidently.
Let us focus on the most common questions of Class 10 Science Viva exams that arise in students’ minds. A subject-wise rundown of the topic from Chemistry to Biology shall help you grasp your basics again, develop your answers well, and feel prepared enough for the examination day. We shall proceed through the subject-wise rundown of such questions and answers.
Chemistry Questions:
Q1. What is quick lime?
Ans. Quick lime is calcium oxide (CaO)
Q2. What is the nature of slaked lime?
Ans. It’s basic by nature.
Q3. What do you observe when water and quick lime are added to a beaker? Can you identify the type of reaction?
Ans. A fast and vigorous reaction place. The beaker becomes hot indicating its exothermic nature. It is an example of a combination reaction.
4. What do you mean by activity series of metals?
Ans. List of metals written in an order where the most reactive metal lies at the top and the least reactive at the bottom,i.e.metals arranged in descending order of their reactivity s called reactivity or activity series of metals.
5. What will you observe if the copper filling is added to green colour ferrous sulphate solutions?
Ans. We will observe no change or reaction as iron can’t be displaced by less reactive copper from its salt solution.
6. A piece of magnesium is put into copper sulphate solutions. What would be the expected observation?
Ans. The blue colour of (CuSO4) copper sulphate solutions will fade and will finally turn colourless. The magnesium piece will be covered by the red-brown coating.
7. If a student is provided with three-piece of metals Zn, Cu and Ag each. Which one he/she will prefer to prepare hydrogen gas using dilute HCl?
Ans. The student will use the piece of Zn metal to produce hydrogen gas as only Zn is more reactive than hydrogen and thus will displace hydrogen from HCl.
8. Mention any two uses of acetic acid in industry.
Ans. (a) It is used as a coagulant in the rubber industry.
(b) Used in the food industry as vinegar.
9. Which gas is evolved when sodium bicarbonate is added to a test tube containing acetic acid?
Ans.Co2,carbondioxide gas
10. A student adds 1 ml of soap solution to 5 ml of water. He observes a foamy appearance inside the test tube. What does this signify?
Ans. The foam produced by the soap signifies good lather formation indicating softness of the water taken in the test tube.
Also Read: CBSE 2025: High-Scoring Topics For Class 10 & 12
Physics Questions:
1. State Ohm’s law.
Ans. Ohm’s law states that if physical conditions like temperature remain constant or the same the current(I) flowing through a conductor is directly proportional to the potential difference(V) applied across the ends.
i.e V ∞ I
or V = IR Where R = resistance of the conductor
2. Is Ohm’s law true for all materials?
Ans. It doesn’t hold good for electronic devices and non-ohmic resistance. Like semi-conductor diodes.
3. Define the potential difference. State whether the potential difference of a cell is smaller than its e.m.f.
Ans. The amount of work done when a single unit charge (1 coulomb) flows from one point to another point in a circuit.
Potential difference is smaller than e.m.f. is used in overcoming the internal resistance of a cell when current is drawn from it.
4. What is electric current?
Ans. The rate of flow of charge or electrons through a conductor is called electric current. Its SI unit is ampere (A).
5. Why copper wire is used in electric circuits?
Ans. Copper metal is a very good conductor of electricity. It has many free electrons to conduct current. It is not very expensive also.
6. Define resistance.
Ans. The obstruction or opposition to the normal flow of current by the conductor when current is flowing through it is called resistance. Its SI unit is ohm(Ω).
7. Is the equivalent resistance of a parallel combination greater than the individual resistance?
Ans.No, its value is smaller than the individual resistance if placed in series or separately.
8. Why rheostat of low resistance is used?
Ans. A rheostat of low resistance keeps the option open for a large variation in resistance thus causing a variety of current flow in the circuit to take many readings.
9. State Snell’s law of refraction.
Ans. According to Snell’s law, the ratio of the sine of the angle of refraction is a constant, for a light ray of a given colour and a given pair of media.
10. State the relationship between ∠i (incident angle) and ∠A(angle of prism) of an optical glass prism.
Ans. ∠i + ∠e = ∠A + ∠δ
Where ∠i = angle of incidence, ∠e = angle of convergence, ∠A = angle of prism, ∠δ =angle of deviation.
Also Read: CBSE Board Exams 2025: Key Changes and Updates You Need To Know
Biology Questions:
1. Why are stomata absent in roots?
Ans. As a little gas exchange takes place in roots hence stomata are not present in them.
2. What is transpiration?
Ans. The loss of water in the form of vapours from the surface of leaves is called transpiration.
3. What are the function of the stomatal apparatus?
Ans. The functions of the stomata are:
(a) For the exchange of gases during respiration and photosynthesis.
(b) During transpiration for loss of water.
4. What is the full form of ATP?
Ans. Adenosine Triphosphate is an energy-rich molecule.
5. What is asexual reproduction?
Ans. It is a mode of reproduction in which a single organism produces new organisms without the formation of ay special cell(gamete). A single parent produces two or more individuals.
6. Is budding in yeast different from hydra? Justify your answer.
Ans. In yeast, budding occurs in the form of a protuberance on the parent yeast cell. It may separate or may not separate and can further develop into several daughter buds. In hydra, the bud separates due to repeated mitotic cell division and is a multicellular single organism itself.
7. Which type of cell division is involved in binary fission?
Ans. Mitosis, as the number of chromosomes, remains the same.
8. Define fermentation.
Ans. It is a type of anaerobic respiration. It also releases CO2 as a by-product.
9. Do the guard cells have rigid or elastic walls? Justify your answers.
Ans. Guard cells have thicker cell walls on the inner side than on the outer side. This adds to their flexibility while opening and closing.
10. How will one identify a monocot leave and a dicote leave based on stomata?
Ans. The guard on the monocot leaves is dumb-bell shaped while in dicot leaves they are kidney-shaped or bean-shaped.
Also Read: Class 10 Chapter-Wise Notes by Gaurav Suthar
Conclusion
Preparing for the Class 10 Science Viva exam is not a challenge at all. A clear idea of frequently asked questions and their answers will help you to face the viva confidently and clearly. The guide provided essential concepts of Chemistry, Physics, and Biology so that you can handle all the most common questions examiners may ask you.
Remember that revising the basics is essential and maintaining a cool-headed situation in an exam hall helps in producing answers more coherently. So, now this one-stop source material may turn out to be helpful, acting like a mini quick revision help desk; be well-prepared for the viva of Class 10 Boards, good luck.
