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CBSE Class 8 Science Chapter-wise MCQs with Answers
Practise CBSE Class 8 Science multiple-choice questions aligned to the CBSE Class 8 syllabus (NCERT-aligned). WeloScholars covers all 13 topics — including Exploring the Investigative World of Science, Microorganisms (The Invisible Living World), Health and Diseases (The Ultimate Treasure), Electricity: Magnetic and Heating Effects — with curriculum-aligned MCQs, an AI tutor that explains every concept step by step, and analytics that show exactly where to focus next. Every question includes a clear explanation of the correct answer and why each distractor is wrong, building real conceptual understanding. Start free: no credit card needed, and your first practice session takes under a minute to set up.
All 13 CBSE Class 8 Science topics
- Exploring the Investigative World of ScienceIdentify and formulate a testable question or problem based on observations or curiosity.
- Microorganisms (The Invisible Living World)List the five major groups of microorganisms: bacteria, fungi, protozoa, algae, and viruses.
- Health and Diseases (The Ultimate Treasure)Distinguish between health and disease, understanding that being disease-free does not necessarily mean being healthy.
- Electricity: Magnetic and Heating EffectsIdentify materials as good or poor conductors of electricity.
- Exploring ForcesDefine force as a push or a pull.
- Pressure, Winds, Storms, and CyclonesExplain that air exerts pressure.
- Particulate Nature of MatterDefine matter and classify it based on its physical states (solid, liquid, gas).
- Nature of Matter: Elements, Compounds, and MixturesClassify various substances as elements, compounds, or mixtures based on their properties and composition.
- Solutions, Solutes and SolventsDefine solute, solvent, and solution.
- Light: Mirrors and LensesState the Laws of Reflection and Laws of Refraction.
- Motions of the Earth and Moon (Keeping Time with the Skies)Describe how the Earth's rotation causes day and night and the apparent movement of the Sun.
- Ecosystems and Food Chains (How Nature Works in Harmony)Define ecosystem and identify its components (biotic and abiotic).
- Our Home: Earth, a Unique Life Sustaining PlanetIdentify Earth as a unique planet supporting life due to specific conditions.
Try 5 CBSE Class 8 Science practice questions with answers
Four students observed that a turmeric paper strip turned reddish-brown when dipped in soap solution, but remained yellow in vinegar. They made the following statements: 1. Turmeric acts as an indicator that changes color in a basic medium. 2. Vinegar is neutral because it does not change the color of turmeric. 3. The experiment proves that any liquid changing turmeric to red must be harmful. 4. Repeating the test with standard baking soda solution helps verify whether alkalinity causes the color change. Which statement(s) is/are scientifically valid based on these observations?
- A. 2 and 4 only
- B. 1 and 2 only
- C. 1 and 3 only
- D. 1 and 4 only
✅ Answer: D
Statement 1 is valid because turmeric turns reddish-brown in basic solutions like soap. Statement 4 is valid as testing another known base (baking soda) verifies replicability and tests the hypothesis. Statement 2 is invalid because turmeric stays yellow in both acidic and neutral media (vinegar is acidic). Statement 3 confuses correlation with an unfounded claim of toxicity. Students often assume unchanged indicator color implies neutrality or draw unwarranted causal conclusions.
A doctor diagnosed Rahul with a viral infection causing high fever and a runny nose, but did not prescribe penicillin or any other antibiotic. Which of the following is the scientific reason for the doctor's decision?
- A. Antibiotics weaken the immune system if taken during any viral fever.
- B. Viruses lack their own biochemical pathways that antibiotics target.
- C. Viruses have thicker cell walls than bacteria, preventing drug absorption.
- D. Penicillin only cures chronic non-infectious conditions.
✅ Answer: B
Antibiotics inhibit essential biochemical pathways specific to bacteria (such as cell wall synthesis); viruses utilise the host's machinery and lack these pathways. Misconception: Thinking antibiotics treat all infectious pathogens including viruses, or that viruses possess cell walls.
Rohan packed sliced mangoes into four jars under different conditions to find the best way to prevent fungal and bacterial growth. Jar 1: Kept open to air at room temperature Jar 2: Submerged completely in concentrated sugar syrup with a tight lid Jar 3: Kept in warm, moist air inside a closed lid Jar 4: Sprinkled with a small amount of plain water and sealed Which jar will remain unspoiled for the longest time, and what is the primary reason?
- A. Jar 4, because sealed plain water keeps food fresh without any chemicals
- B. Jar 2, because high sugar content draws moisture out of microbial cells to inhibit growth
- C. Jar 3, because warm temperatures destroy all microbial enzymes
- D. Jar 1, because continuous air circulation dries out microorganisms
✅ Answer: B
Concentrated sugar syrup acts as a preservative by reducing available moisture, preventing microbial growth. Misconception: Believing warm conditions kill all microbes or thinking all food preservatives must be artificial toxic chemicals.
Rohan designed an experiment to test whether adding vermicompost increases the growth rate of tomato seedlings over two weeks. Which of the following set-ups serves as the most appropriate control setup for this investigation?
- A. A seedling grown in sterile sand with no water or sunlight
- B. A seedling grown in identical garden soil with chemical urea fertilizer added
- C. A seedling grown in identical garden soil under identical conditions without vermicompost
- D. A mature flowering tomato plant grown with double the amount of vermicompost
✅ Answer: C
A control setup must be identical in all respects to the experimental setup except for the absence of the independent variable (vermicompost) to provide a valid baseline for comparison. Changing soil type, withholding essential factors like water, or testing a different growth stage introduces confounding variables. Students often confuse a control setup with a controlled variable or alter multiple variables at once.
In a village, the following sequence of events was observed after heavy flooding: (1) Open drains overflowed and mixed with local drinking-well water. (2) Pathogenic bacteria multiplied in the contaminated drinking source. (3) Villagers ingested the pathogen by drinking untreated water. (4) A large outbreak of acute watery diarrhoea spread across the village. To break this transmission cycle and prevent future outbreaks of this water-borne disease, three health volunteers proposed the following measures: Volunteer X: Provide boiled or chlorinated water to all households. Volunteer Y: Spray insecticides outdoors to eliminate flying insect vectors. Volunteer Z: Construct closed drainage systems away from drinking water wells. Which volunteer(s) proposed effective measures directly addressing the chain of transmission?
- A. Volunteer X and Volunteer Z only
- B. Volunteer X only
- C. Volunteer Y and Volunteer Z only
- D. Volunteer Y only
✅ Answer: A
Step 1 is broken by proper sewage containment (Volunteer Z), and Step 3 is broken by safe drinking water disinfection (Volunteer X). Diarrhoeal diseases like cholera are water-borne, not insect-vector-borne. Misconception: Believing all seasonal epidemic outbreaks are transmitted by insect vectors like mosquitoes or flies.
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Frequently asked questions
Is this aligned to the NCERT/CBSE 2026–27 syllabus?
Yes. WeloScholars maps every CBSE Class 8 Science question to the official syllabus, topic by topic, and updates when the syllabus changes. Off-syllabus content is excluded.
How many CBSE Class 8 Science topics are covered?
All 13 topics in the CBSE Class 8 Science curriculum, each with its own question pool, learning objectives and AI tutor support.
Can my child practise CBSE Class 8 Science for free?
Yes. The free plan includes practice questions every month plus a demo you can try without creating an account. Premium unlocks unlimited practice and full explanations.
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