Class 10 practice
Class 10 science questions.
Science questions for Class 10, at the level of students aged 15–17, each with its answer and a short explanation. Try each one before opening the answer.
In humans, which chamber of the heart receives oxygen-rich blood directly from the lungs via the pulmonary veins?
Level 1 of 5Show the answer
Answer: Left atrium
Pulmonary veins carry oxygenated blood from the lungs into the left atrium. It then flows into the left ventricle to be pumped throughout the body.
Which plant tissue is primarily responsible for the transport of water and dissolved minerals from the roots up to the leaves?
Level 1 of 5Show the answer
Answer: Xylem
Xylem vessels conduct water and dissolved minerals upward from roots to leaves, whereas phloem transports food synthesised in the leaves.
Although Mercury orbits closest to the Sun, Venus records the highest average surface temperature among all planets. Which atmospheric factor primarily accounts for this extreme heat?
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Answer: A dense atmosphere dominated by carbon dioxide
Venus has a dense atmosphere rich in carbon dioxide, which creates a powerful runaway greenhouse effect that traps solar thermal radiation.
When a beam of white light passes through a triangular glass prism, it separates into a band of distinct colours. What is this phenomenon called?
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Answer: Dispersion
Dispersion occurs because different colours of light refract by different angles when passing through a prism, splitting white light into its spectrum.
During the decomposition of calcium carbonate in a laboratory kiln, thermal energy must be continuously supplied to sustain the reaction. What term describes this classification of chemical process?
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Answer: Endothermic reaction
An endothermic reaction absorbs heat energy from its surroundings to break chemical bonds and drive the conversion of reactants into products.
During a chemistry practical in school, Ananya adds a few drops of phenolphthalein to an aqueous solution of sodium hydroxide. What distinct colour change indicates the alkaline nature of this solution?
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Answer: Turns deep pink
Phenolphthalein is a synthetic indicator that remains colourless in acidic or neutral solutions. In basic solutions, such as sodium hydroxide, it turns pink.
- True or false?
A concave mirror always produces an inverted image regardless of where an object is placed along its principal axis.
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Answer: False
When an object is placed between the pole and the principal focus of a concave mirror, it forms an erect, magnified, and virtual image behind the mirror.
- Fill in the blank.
The lowest layer of Earth's atmosphere, where nearly all meteorological weather events occur, is the ___ (first letter: t).
Level 1 of 5Show the answer
Answer: troposphere
The troposphere contains roughly three-quarters of the atmosphere's mass and almost all its water vapour, making it the site of weather systems.
Rohan pushes a stationary 5 kg wooden box across a smooth floor using a constant net horizontal force of 20 N. What acceleration does the box experience?
Level 2 of 5Show the answer
Answer: 4 m/s²
According to Newton's second law of motion, acceleration equals net force divided by mass. Dividing 20 N by 5 kg yields 4 m/s².
In a classical genetics cross between pure tall and pure dwarf pea plants, Mendel observed the F1 generation. What phenotypic ratio appeared in the subsequent F2 generation?
Level 2 of 5Show the answer
Answer: 3 tall to 1 dwarf
Self-pollination of heterozygous F1 plants yields three offspring showing the dominant tall phenotype for every one showing the recessive dwarf phenotype.
During intense physical exertion such as sprinting, human muscle cells experience temporary oxygen deficiency. Through which metabolic pathway do these cells produce energy, leading to the accumulation of a specific organic compound?
Level 2 of 5Show the answer
Answer: Anaerobic respiration producing lactic acid
Under insufficient oxygen supply, pyruvate in muscle cells is converted into lactic acid via anaerobic respiration. This pathway releases a small amount of energy quickly.
In the human circulatory system, which blood vessel transports deoxygenated blood directly from the right ventricle of the heart to the lungs?
Level 2 of 5Show the answer
Answer: Pulmonary artery
The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs for oxygenation. Pulmonary veins then return the oxygenated blood to the left atrium.
During a laboratory exercise in Bhopal, Rohan bubbles carbon dioxide gas through freshly prepared lime water. The clear solution initially turns milky due to the formation of a precipitate. Which compound causes this white turbidity?
Level 2 of 5Show the answer
Answer: Calcium carbonate
Carbon dioxide reacts with aqueous calcium hydroxide to produce insoluble calcium carbonate, creating the characteristic milky suspension.
In extractive metallurgy, sulphide ores are typically converted into metal oxides prior to chemical reduction. Which thermal operation involves heating sulphide ore strongly below its melting point in excess air?
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Answer: Roasting
Roasting converts sulphide ores into oxides by heating them in the presence of excess oxygen, releasing sulphur dioxide gas.
- True or false?
Pure water at 25 degrees Celsius has a neutral pH of 7 because the concentration of hydronium ions equals that of hydroxide ions.
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Answer: True
Autoionisation of water yields equal concentrations of hydronium and hydroxide ions (10^-7 moles per litre) at 25 degrees Celsius, defining neutrality.
- True or false?
The acceleration due to gravity on Earth is constant and identical at the equator and at the geographic poles.
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Answer: False
Because Earth is flattened at the poles and bulges at the equator, polar radius is smaller, making gravitational acceleration slightly higher at the poles.
- Fill in the blank.
The unique ability of carbon atoms to link together to form long chains and branched rings is termed ___ (first letter: c).
Level 2 of 5Show the answer
Answer: catenation
Catenation is the linkage of atoms of the same element into longer chains, a property carbon exhibits exceptionally well.
- Fill in the blank.
The microscopic junction across which an electrical nerve impulse is transmitted between two adjacent neurons is a ___ (s______).
Level 2 of 5Show the answer
Answer: synapse
A synapse is the functional gap between neurons where neurotransmitters convey chemical signals from one cell to another.
Which of the following units of measurement is the odd one out?
Level 2 of 5Show the answer
Answer: Joule
Candela, Kelvin, and Ampere are fundamental base SI units, whereas the Joule is a derived unit.
Identify the odd one out among these wave phenomena.
Level 2 of 5Show the answer
Answer: Ultrasonic waves
Infrared radiation, microwaves, and ultraviolet rays are electromagnetic waves that travel through a vacuum. Ultrasonic waves are mechanical sound waves that require a material medium.
These questions come from Ado’s question bank and are written with AI help. They are never used in ranked play, so practising them here can’t change anyone’s rank.
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