Class 12 Boards : Most Common Viva Questions in Physics and Chemistry with Answers

Most Common Viva Questions in Physics and Chemistry with Answers:: Viva exams are an essential part of practical assessments in Physics and Chemistry. These oral examinations test students’ understanding of concepts, their ability to apply knowledge, and their analytical skills. In this blog post, we will discuss some of the most common viva questions in Physics and Chemistry along with their answers.

Viva Questions for Class 12 Physics & Chemistry

Why it matters: Viva voce is crucial in Class 12 practical exams. It tests your conceptual grasp beyond just performing experiments.

What to expect: Expect questions related to experiment principles, applications, and underlying theory.

How to prepare:

• Thoroughly revise theory.
• Practice past year questions.
• Understand the “why” and “how” of concepts.

The Role of Viva Voce in Class 12 Science Practical Examinations

Viva Objectives:

• Conceptual Understanding: Test your grasp of fundamental concepts.
• Procedural Knowledge: Assess familiarity with experiment procedures and principles.
• Application Skills: Gauge your ability to apply theory to practical situations.

Preparation Tips:

• Revise Theory: Thoroughly review the theory behind experiments.
• Practice Questions: Practice past year viva questions.
• Focus on “Why” & “How”: Understand the rationale and methodology behind concepts.

Most Asked Viva Questions in Class 12 Physics Practical Exams

Physics practicals include experiments in optics, electricity, magnetism, and mechanics. Here are some frequently asked viva questions for Physics:

Here are the answers in the simplest form possible:

1. Optics

Q. How do concave mirrors and convex lenses function?

• Concave mirrors converge light to a point.
• Convex lenses refract light to converge it at a point.

Q. What is focal length, and how do you determine it?

• Focal length is how far the lens/mirror is from the point where light comes together. It’s found through formula or by heating sunlight onto a screen.

Q. Why use the parallax method of lens focal length?

• In order to obtain a precise measurement through proper alignment of images.

Q. What is the difference between real and virtual images?

• Real images can be projected onto a screen.
• Virtual images cannot be projected; they are inside the mirror/lens.

Q. Why is a convex lens used as a magnifying glass?

• It makes objects larger by forming a larger virtual image.

2. Electricity

Q. What is Ohm’s Law, and how do you prove it?

• Ohm’s Law: Voltage = Current × Resistance (V = IR).
• Demonstrate it by measuring the voltage and current in a circuit and seeing whether V/I remains constant.

Q. What is resistivity, and how does it vary with temperature?

• Resistivity is a substance’s opposition to electric flow.

• It rises with temperature in metals and falls in semiconductors.

Q. What is the function of a rheostat in a circuit?

• It regulates current by adjusting resistance.

Q. Why employ a Wheatstone bridge?

• To quantify unknown resistance with great precision.

Q. What are the merits of a potentiometer over a voltmeter?

• More precise since it doesn’t take current from the circuit.

3. Magnetism

Q. How does a galvanometer work?

• It senses tiny electric currents by deflecting a needle using a magnetic field.

Q. How do you find the magnetic field using a tangent galvanometer?

• By calculating the angle of deflection when current passes through its coil.

Q.What is magnetic flux?

• The total amount of magnetic field cutting through a surface.

Q.What influences the magnetic field in a solenoid?

• The number of turns, the current, and the core material.

4. General

Q. What are systematic and random errors?

• Systematic errors are regular errors (such as defective instruments).
• Random errors occur at random (such as hand shaking).

Q. Why are optics experiments performed in dark rooms?

• In order to observe light paths and images clearly.

Q. What is the least count?

• The minimum amount an instrument can measure with accuracy.

Q. Why do we take repeated readings in experiments?

• To minimize errors and obtain more precise results.

Most Common Viva Questions in Physics and Chemistry with Answers

Most Asked Viva Questions in Class 12 Chemistry Practical Exams

Chemistry Viva Questions (Class 12)

1. Titrations

• What is titration?
  A method to find the concentration of a solution by reacting it with a solution of known concentration.
• Why do we use indicators?
  To show when the reaction is complete by changing color.
• Why use phenolphthalein?
  It changes color in acid and base, making it easy to see the endpoint.
• What does the endpoint mean?
  The point when the reaction is complete, shown by a color change.
• Why clean the burette and pipette?
  To remove impurities and ensure accurate measurements.

2. Qualitative Analysis

• What’s the difference between cations and anions?
  Cations are positive (+) ions, and anions are negative (-) ions.
• Why use ammonium hydroxide?
  It helps in identifying metal ions by forming precipitates.
• How to find sulfate ions?
  Add barium chloride; a white precipitate confirms sulfate ions.
• What’s the flame test for?
  To determine metal ions by the color they yield in a flame.
• Why do some salts color the flame?
  Because metal ions give off certain colors when heated.

3. Salt Analysis

• What are group reagents?
  Chemicals that are used to divide ions into groups so that they can be identified.
• How to find carbonate ions?
  Add acid; if bubbles occur, it is an indication that carbonate ions exist.
• Why use diluted HCl?
  It dissolves salts and identifies gases in salt examination.
• How to check for chloride ions?
  Add silver nitrate; the formation of a white precipitate indicates chloride.

4. Chemical Reactions

• What is a redox reaction?
  A reaction in which one material gains oxygen (oxidation) and another loses oxygen (reduction).
• How is oxidation and reduction different?
  Oxidation: Loss of oxygen or gain of electrons.
  Reduction: Gain of oxygen or loss of electrons.
• Why is KMnO₄ a self-indicator?
  It is purple and colorless when the reaction is over.
• Why distilled water?
  In order not to have impurities that would impact the reaction.

5. General Questions

• Safety regulations for titration?
  Wear goggles, use a pipette filler, and use acids/bases with caution.
• Why standard solutions?
  For the precision of chemical reactions.
• What’s molarity versus normality?
• Molarity (M): Number of moles of solute per liter of solution.
• Normality (N): Equivalent number of moles per liter of solution.
• What do temperature and pressure do to reactions?
  Increased temperature accelerates reactions; increased pressure influences gas reactions.

Is there anything else I can simplify for you? ????

Remember: The best way to understand is to practice answering these questions out loud!

Most Common Viva Questions in Physics and Chemistry with Answers

Most Important Tips to Prepare for Viva

• Familiarize yourself thoroughly with the principles, procedures, and calculations for each experiment. Ensure you understand the purpose of every apparatus involved.
• Revise Concepts
  Refresh your knowledge of theoretical concepts related to practicals, including key definitions, formulas, and derivations.
• Refer to NCERT Lab Manuals
  Use NCERT lab manuals as your primary study resource. They provide detailed, step-by-step explanations of experiments and commonly asked viva questions.
• Be Honest
  If you’re unsure about an answer, politely admit it rather than giving an incorrect response.
• Review Previous Year Questions
  Look over viva questions from previous school or board exams to get a sense of what examiners typically ask.
• Stay Calm and Confident
  Avoid letting nervousness cause unnecessary mistakes. Listen carefully to each question, and respond with confidence.

Most Common Viva Questions in Physics and Chemistry with Answers

Final Words

Viva exams can seem daunting, but with proper preparation, you can ace them with ease. Focus on understanding the principles behind the experiments rather than memorizing answers. Be confident in your approach, and don’t hesitate to clarify doubts with your teacher during the lab sessions.

Remember, the key to excelling in viva is not just theoretical knowledge but also the ability to apply it practically. All the best for your Class 12 Physics and Chemistry practical exams!

ALSO READ:: Class 12 Maths NCERT Solutions

Most Common Viva Questions in Physics and Chemistry with Answers

FAQs related to Most Common Viva Questions in Physics and Chemistry with Answers:

1. How should I prepare for a Physics and Chemistry viva?

To prepare effectively, focus on understanding fundamental concepts rather than rote memorization. Revise key definitions, formulas, and laws. Practice explaining concepts aloud, and if possible, engage in mock viva sessions.

2. What are the most commonly asked topics in a viva exam?

Common topics in Physics include Newton’s Laws, Ohm’s Law, Work and Energy, Electricity, and the Doppler Effect. In Chemistry, frequent topics include the Periodic Table, Acids and Bases, Electrolysis, Redox Reactions, and pH concepts.

3. How can I handle difficult questions in a viva?

If you don’t know the answer, stay calm and try to logically deduce it based on related concepts. If unsure, politely ask for clarification or explain what you do know about the topic.

4. Is it necessary to remember all formulas in Physics and Chemistry?

Yes, but understanding their derivations and applications is more important. Knowing the context in which a formula is used will help you recall it more effectively.

5. How important is confidence in a viva exam?

Confidence plays a significant role. Even if you are unsure of an answer, responding clearly and logically can leave a positive impression on the examiner. Stay composed and answer to the best of your ability.

Most Common Viva Questions in Physics and Chemistry with Answers