These essential MCQ questions are selected from the most important topics in CBSE Class 8 Science 2026 as per the latest NCERT syllabus. Sections include Crop Production & Management, Microorganisms, Metals & Non-Metals, Force & Pressure, Light, and Cell Structure & Functions. For truly unlimited daily MCQ practice, visit Vooo AI Education.
🔬 CBSE Class 8 Science
1Which of the following is a Kharif crop?
Answer: C — Paddy
Kharif crops are sown in June–July with the onset of monsoon and harvested in September–October. Paddy (rice), maize, cotton, and soyabean are Kharif crops. Wheat, mustard, and gram are Rabi crops, sown in October–November and harvested in March–April. Remember: Kharif = rainy season crops.
Kharif crops are sown in June–July with the onset of monsoon and harvested in September–October. Paddy (rice), maize, cotton, and soyabean are Kharif crops. Wheat, mustard, and gram are Rabi crops, sown in October–November and harvested in March–April. Remember: Kharif = rainy season crops.
2Which microorganism is used to make bread and idli dough rise?
Answer: B — Yeast
Yeast is a fungus (microorganism) that reproduces rapidly and produces carbon dioxide gas during fermentation. This CO₂ makes the dough rise and become soft and spongy. Yeast is also used in making wine and beer. It is a single-celled organism and is very useful in the food industry. Bacteria like Lactobacillus are used in making curd.
Yeast is a fungus (microorganism) that reproduces rapidly and produces carbon dioxide gas during fermentation. This CO₂ makes the dough rise and become soft and spongy. Yeast is also used in making wine and beer. It is a single-celled organism and is very useful in the food industry. Bacteria like Lactobacillus are used in making curd.
3Which of the following is a property of metals?
Answer: B — Good conductor of heat
Metals are generally good conductors of both heat and electricity. They are malleable (can be beaten into sheets), ductile (can be drawn into wires), lustrous (shiny), and sonorous (produce a ringing sound). Non-metals are poor conductors, brittle, and dull in appearance. Exception: Mercury is a liquid metal at room temperature.
Metals are generally good conductors of both heat and electricity. They are malleable (can be beaten into sheets), ductile (can be drawn into wires), lustrous (shiny), and sonorous (produce a ringing sound). Non-metals are poor conductors, brittle, and dull in appearance. Exception: Mercury is a liquid metal at room temperature.
4The force acting on a unit area of a surface is called:
Answer: C — Pressure
Pressure = Force / Area. It is the force acting perpendicularly on a unit area of a surface. The SI unit of pressure is Pascal (Pa), where 1 Pa = 1 N/m². Thrust is the total force acting on a surface. Pressure explains why a sharp knife cuts better (small area → more pressure) and why camels can walk on sand (large feet → less pressure).
Pressure = Force / Area. It is the force acting perpendicularly on a unit area of a surface. The SI unit of pressure is Pascal (Pa), where 1 Pa = 1 N/m². Thrust is the total force acting on a surface. Pressure explains why a sharp knife cuts better (small area → more pressure) and why camels can walk on sand (large feet → less pressure).
5Which phenomenon causes the sky to appear blue?
Answer: C — Scattering of light
Sunlight is scattered by tiny air molecules in the atmosphere. Blue light has a shorter wavelength and is scattered much more than red light (which has a longer wavelength). This scattered blue light reaches our eyes from all directions making the sky appear blue. During sunrise and sunset, light travels a longer path so blue light is scattered away and red/orange colours remain, causing the red sky.
Sunlight is scattered by tiny air molecules in the atmosphere. Blue light has a shorter wavelength and is scattered much more than red light (which has a longer wavelength). This scattered blue light reaches our eyes from all directions making the sky appear blue. During sunrise and sunset, light travels a longer path so blue light is scattered away and red/orange colours remain, causing the red sky.
6The powerhouse of the cell is:
Answer: C — Mitochondria
Mitochondria are the sites of cellular respiration where energy (ATP) is produced from glucose. Hence they are called the powerhouse of the cell. The nucleus controls all cell activities and contains DNA. Ribosomes are the sites of protein synthesis. Vacuoles store food, water, or waste materials. Chloroplasts (found in plant cells) are the sites of photosynthesis.
Mitochondria are the sites of cellular respiration where energy (ATP) is produced from glucose. Hence they are called the powerhouse of the cell. The nucleus controls all cell activities and contains DNA. Ribosomes are the sites of protein synthesis. Vacuoles store food, water, or waste materials. Chloroplasts (found in plant cells) are the sites of photosynthesis.
7Which gas is produced when dilute hydrochloric acid reacts with zinc?
Answer: B — Hydrogen
When zinc reacts with dilute HCl, zinc chloride and hydrogen gas are produced: Zn + 2HCl → ZnCl₂ + H₂↑. Hydrogen gas burns with a 'pop' sound when a burning splinter is brought near it — this is the test for hydrogen. Metals above hydrogen in the reactivity series can displace hydrogen from dilute acids. Gold and silver do not react with dilute acids.
When zinc reacts with dilute HCl, zinc chloride and hydrogen gas are produced: Zn + 2HCl → ZnCl₂ + H₂↑. Hydrogen gas burns with a 'pop' sound when a burning splinter is brought near it — this is the test for hydrogen. Metals above hydrogen in the reactivity series can displace hydrogen from dilute acids. Gold and silver do not react with dilute acids.
8Nitrogen fixation by bacteria takes place in the:
Answer: C — Root nodules of legumes
Rhizobium bacteria live in the root nodules of leguminous plants like peas, beans, and groundnuts. These bacteria fix atmospheric nitrogen (N₂) into usable nitrates/nitrites that enrich the soil. This is why farmers rotate crops with legumes to improve soil fertility. This is an example of a symbiotic relationship — the bacteria get food and shelter from the plant; the plant gets fixed nitrogen.
Rhizobium bacteria live in the root nodules of leguminous plants like peas, beans, and groundnuts. These bacteria fix atmospheric nitrogen (N₂) into usable nitrates/nitrites that enrich the soil. This is why farmers rotate crops with legumes to improve soil fertility. This is an example of a symbiotic relationship — the bacteria get food and shelter from the plant; the plant gets fixed nitrogen.
9A convex mirror is used as a rear-view mirror in vehicles because:
Answer: B — It gives a wider field of view
A convex mirror always forms a virtual, erect, and diminished image regardless of object distance. Because the image is smaller, it covers a wider area in the mirror, giving the driver a broader field of view behind the vehicle. This makes it safer for driving. Concave mirrors are used as shaving/makeup mirrors as they form magnified images when object is within focal length.
A convex mirror always forms a virtual, erect, and diminished image regardless of object distance. Because the image is smaller, it covers a wider area in the mirror, giving the driver a broader field of view behind the vehicle. This makes it safer for driving. Concave mirrors are used as shaving/makeup mirrors as they form magnified images when object is within focal length.
10The process by which green plants make their own food is called:
Answer: C — Photosynthesis
Photosynthesis is the process by which green plants use sunlight, water (from soil), and carbon dioxide (from air) to produce glucose and oxygen. Equation: 6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂. Chlorophyll in chloroplasts absorbs sunlight. Plants are called autotrophs (self-feeders) because of this. Oxygen released during photosynthesis is vital for all living organisms.
Photosynthesis is the process by which green plants use sunlight, water (from soil), and carbon dioxide (from air) to produce glucose and oxygen. Equation: 6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂. Chlorophyll in chloroplasts absorbs sunlight. Plants are called autotrophs (self-feeders) because of this. Oxygen released during photosynthesis is vital for all living organisms.
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