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Previous Year Questions

CBSE Class 9 Science
PYQ & Important Questions

Chapter-wise important questions  ·  Physics, Chemistry & Biology  ·  New 2026-27 syllabus

New syllabus from 2026-27. This is the first year of the new NCERT Class 9 Science book, so no previous-year papers exist for it yet. Until then, this page lists chapter-wise important questions in the exam pattern, with marks. Actual previous-year questions will be added after the 2027 annual exams.

01 Exploration: Entering the World of Secondary Science 10 questions
1
What is the physical state of water at (a) 25°C, (b) 100°C, (c) 250°C?
1 Mark
2
Convert the following temperatures to the Celsius scale: (a) 300 K, (b) 573 K.
1 Mark
3
Why does steam at 100°C cause more severe burns than boiling water at the same temperature?
2 Marks
4
A student observes that while boiling water the temperature remains constant at 100°C even though heat is still being supplied. Explain why, and name the heat absorbed during this process.
2 Marks
5
Define latent heat of fusion. How much heat is needed to convert 1 kg of ice at 0°C into water at 0°C? (Latent heat of fusion of ice = 334 J/g)
2 Marks
6
Arrange the following in increasing order of forces of attraction between their particles: water, sugar, oxygen.
1 Mark
7
Why does a desert cooler cool better on a hot, dry day compared to a humid day? Explain using the concept of evaporation.
2 Marks
8
Tabulate the differences between solids, liquids and gases in terms of shape, volume, compressibility and fluidity.
3 Marks
9
List the four factors that affect the rate of evaporation of a liquid. Explain each briefly.
3 Marks
10
A sample of water was found to boil at 102°C at normal atmospheric pressure. Is the water pure? Will this water freeze at 0°C? Give reasons.
2 Marks
02 Exploring Mixtures and their Separation 10 questions
1
Identify the solutions among the following mixtures: soil, sea water, air, coal, soda water.
1 Mark
2
Which of the following will show the Tyndall effect? Salt solution, milk, copper sulphate solution, starch solution.
1 Mark
3
List the two conditions essential for using distillation as a method for separating the components of a mixture.
2 Marks
4
Water is a compound and not a mixture. Justify this statement giving two reasons.
2 Marks
5
To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find the concentration in terms of mass-by-mass percentage of the solution.
2 Marks
6
Distinguish between a true solution, a colloidal solution and a suspension on the basis of particle size and Tyndall effect.
3 Marks
7
Name the separation technique used to separate cream from milk. Explain the principle behind this method.
2 Marks
8
How will you separate a mixture containing kerosene and petrol (difference in their boiling points is less than 25 K)? Explain the process and draw a labelled diagram of the apparatus used.
3 Marks
9
Classify the following as elements, compounds and mixtures: sodium, soil, sugar solution, silver, calcium carbonate, air.
2 Marks
10
Why is crystallisation considered a better technique than simple evaporation for purification of a substance? Give one example where crystallisation is used.
2 Marks
03 Atomic Foundations of Matter 10 questions
1
State the law of conservation of mass. Who proposed it?
1 Mark
2
Write the chemical formula of: (a) aluminium sulphate, (b) calcium phosphate, (c) ammonium chloride.
1 Mark
3
Calculate the molar mass of: (a) H2O, (b) HNO3, (c) CO2.
2 Marks
4
State the law of definite proportions (law of constant composition). Give one example to illustrate it.
2 Marks
5
Convert the following into moles: (a) 12 g of oxygen gas (O2), (b) 20 g of water, (c) 22 g of carbon dioxide.
2 Marks
6
Calculate the number of molecules in 5.6 L of CO2 at STP. (Avogadro's number = 6.022 × 1023)
2 Marks
7
Aluminium has valency 3 and oxygen has valency 2. Write the formula of aluminium oxide and calculate its molar mass. (Al = 27, O = 16)
2 Marks
8
A 0.24 g sample of a compound of oxygen and boron was found to contain 0.096 g of boron and 0.144 g of oxygen. Calculate the percentage composition of the compound by weight.
3 Marks
9
Calculate the number of atoms present in: (a) 52 g of helium (He), (b) 12 g of helium. (He = 4 u)
3 Marks
10
What is the significance of the mole concept? Calculate the mass of 3 moles of sulphur dioxide (SO2). (S = 32, O = 16)
3 Marks
04 Journey Inside the Atom 10 questions
1
State any two limitations of Rutherford's nuclear model of the atom.
2 Marks
2
The atomic number of magnesium is 12. Write the electronic configuration of Mg2+ ion. Is it similar to the electronic configuration of any noble gas?
1 Mark
3
Write the distribution of electrons in the orbits of chlorine (atomic number 17). What is the valency of chlorine?
2 Marks
4
Compare the properties of electrons, protons and neutrons with respect to charge, mass and location in the atom.
3 Marks
5
What is an isotope? Give two isotopes of hydrogen. Mention any one use of radioactive isotopes.
3 Marks
6
Define isobars. Give one example. In what way are isobars different from isotopes?
2 Marks
7
An element has mass number 23 and its nucleus contains 12 neutrons. (a) Name the element. (b) Write the number of electrons in its neutral atom. (c) Draw the Bohr's model of its atom.
3 Marks
8
Describe Rutherford's alpha-particle scattering experiment. State the key observations and the conclusions drawn from each observation.
3 Marks
9
Write the postulates of Bohr's model of the atom. State the formula for calculating the maximum number of electrons in any shell.
3 Marks
10
The mass number of element X is 35 and it has 18 neutrons. Find the atomic number of X, identify the element and write its electronic configuration.
2 Marks
05 Cell: The Building Block of Life 10 questions
1
Who discovered the cell? Name the scientists who formulated the cell theory.
1 Mark
2
Why is the plasma membrane called a selectively permeable membrane?
2 Marks
3
What is osmosis? What will happen when a raisin is placed in plain water for a few hours? Explain in terms of osmosis.
3 Marks
4
Compare prokaryotic and eukaryotic cells on the basis of (a) presence of nucleus, (b) cell size, and (c) example organisms.
3 Marks
5
Draw a well-labelled diagram of a plant cell. Label any four organelles and state one function of each.
3 Marks
6
What is the role of vacuoles in plant cells? How does their role differ from vacuoles in animal cells?
2 Marks
7
Write two functions each of: (a) mitochondria, (b) Golgi apparatus.
2 Marks
8
Explain how chromosomes are related to genes. Where are chromosomes located in the cell? What are the units of inheritance?
2 Marks
9
What is diffusion? How does diffusion differ from osmosis? Give one example of each in living organisms.
2 Marks
10
Why do plant cells require a cell wall in addition to the cell membrane? State any two functions of the cell wall.
2 Marks
06 Tissues in Action 10 questions
1
Define a tissue. Why do multicellular organisms have tissues instead of having all the same type of cells?
2 Marks
2
Name the two types of meristematic tissue based on location. Give one example of each.
2 Marks
3
What is the difference between parenchyma and collenchyma? In what ways is sclerenchyma different from both?
3 Marks
4
Draw a labelled diagram of a neuron. State the function of: (a) dendrite, (b) axon, (c) myelin sheath.
3 Marks
5
Differentiate between striated, non-striated and cardiac muscle tissue on the basis of structure, location and whether they are under voluntary or involuntary control.
3 Marks
6
What is epidermis? Why is epidermis important for plants? What special modification does the epidermis have in desert plants?
2 Marks
7
Name the two fluid connective tissues in the human body. What are the functions of each?
2 Marks
8
Xylem and phloem are complex tissues. Justify this by naming all the cellular components of each.
3 Marks
9
What is cork? How is it formed? State two functions of cork in plants.
2 Marks
10
Why are mitotic cell divisions restricted to meristematic tissue in plants? What would happen if other plant cells also divided continuously?
2 Marks
07 Patterns in Life: Diversity and Classification 10 questions
1
Who proposed the five-kingdom classification? Name the five kingdoms.
2 Marks
2
What are the basic criteria used for classifying organisms into different groups?
2 Marks
3
What is the difference between angiosperms and gymnosperms? Give one example of each. Name one plant from each that is economically important.
2 Marks
4
Name the phyla to which each of the following organisms belong: (a) earthworm, (b) prawn, (c) housefly, (d) sea anemone.
2 Marks
5
Write three characteristics of Class Mammalia. Give two examples of mammals.
3 Marks
6
Distinguish between monocotyledons and dicotyledons. Give two examples of each.
3 Marks
7
State any three features that distinguish fungi from plants.
2 Marks
8
What is binomial nomenclature? Who introduced it? Give the scientific name of (a) mango, (b) human beings.
2 Marks
9
Compare Thallophyta and Bryophyta on the basis of (a) presence of vascular tissue, (b) mode of nutrition, (c) body organisation. Give one example of each.
3 Marks
10
Why is classification of living organisms important? Who is known as the father of taxonomy?
2 Marks
08 Describing Motion Around Us 10 questions
1
Define uniform circular motion. Give one example. Is it an accelerated motion? Why?
2 Marks
2
Distinguish between distance and displacement. Under what condition is the magnitude of displacement equal to the distance?
2 Marks
3
An object is moving with a velocity of 5 m/s. After 10 s its velocity becomes 25 m/s. Calculate the acceleration of the object.
2 Marks
4
Draw a velocity-time graph for an object moving with uniform acceleration starting from rest. How will you calculate the distance covered from this graph?
3 Marks
5
A bus starts from rest and attains a velocity of 60 km/h in 5 minutes. Find: (a) acceleration, (b) distance covered in this period.
3 Marks
6
Derive the third equation of motion: v2 = u2 + 2as, using the first and second equations of motion.
3 Marks
7
A stone is thrown vertically upward with an initial velocity of 20 m/s. Taking g = 10 m/s², find: (a) maximum height reached, (b) time taken to reach maximum height.
3 Marks
8
A racing car has a uniform acceleration of 4 m/s². What distance will it cover in 10 s after the start?
2 Marks
9
Define uniform motion and non-uniform motion. Give one example of each. Is a body moving in a circle at constant speed undergoing uniform or non-uniform motion?
2 Marks
10
A train starting from rest attains a velocity of 72 km/h in 5 minutes. Assuming uniform acceleration, find: (a) acceleration, (b) distance traveled by the train for attaining this velocity.
3 Marks
09 How Forces Affect Motion 20 questions
1
When a carpet is beaten with a stick, dust comes out of it. Which law of Newton does this illustrate? Explain.
2 Marks
2
Why is it advised to tie luggage kept on the roof of a bus with a rope? Which property of matter does this relate to?
2 Marks
3
State Newton's second law of motion. Derive F = ma mathematically from it.
3 Marks
4
A stone of mass 1 kg is thrown with a velocity of 20 m/s across a frozen lake and comes to rest after traveling 50 m. What is the force of friction between the stone and the ice?
2 Marks
5
A bullet of mass 10 g traveling at 150 m/s strikes a stationary wooden block and comes to rest in 0.03 s. Calculate the magnitude of the force exerted by the wooden block on the bullet.
3 Marks
6
State Newton's third law of motion. Explain how a boat is pushed forward when a sailor uses oars.
3 Marks
7
From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 m/s. Calculate the initial recoil velocity of the rifle.
3 Marks
8
An object of mass 1 kg traveling in a straight line at 10 m/s collides with and sticks to a stationary wooden block of mass 5 kg. Calculate the total momentum just before impact and the velocity of the combined object after collision.
3 Marks
9
Explain why it is difficult for a fireman to hold a hose that ejects large amounts of water at high velocity. Which law of Newton explains this?
2 Marks
10
Two objects, each of mass 1.5 kg, are moving toward each other with velocities of 2.5 m/s each. They collide and stick together. What will be the velocity of the combined object after the collision?
3 Marks
11
State the universal law of gravitation. Write its mathematical expression. What is the SI unit of G?
2 Marks
12
Why is 'G' called the universal gravitational constant? What is its value?
1 Mark
13
Give three differences between the acceleration due to gravity (g) and the universal gravitational constant (G).
3 Marks
14
A ball is dropped from a height of 49 m. Calculate its final velocity just before it strikes the ground. (g = 9.8 m/s²)
2 Marks
15
Show that the weight of an object on the Moon is 1/6th of its weight on Earth.
3 Marks
16
A stone dropped from the top of a building takes 4 s to reach the ground. Calculate the height of the building. (g = 10 m/s²)
2 Marks
17
Why does a body reach the ground quicker when dropped at the pole compared to the equator?
2 Marks
18
A force of 20 N acts on a body weighing 9.8 N. Find: (a) mass of the body, (b) acceleration produced. (g = 9.8 m/s²)
3 Marks
19
What will happen to the weight of a body if the Earth's radius doubles while its mass remains the same? Justify your answer.
2 Marks
20
Define: (a) gravitational force, (b) free fall, (c) weight. How is mass different from weight?
3 Marks
10 Work, Energy, and Simple Machines 10 questions
1
Define work. When is work done by a force said to be negative? Give one example.
2 Marks
2
A lamp consumes 1000 J of electrical energy in 10 s. What is its power?
1 Mark
3
Define kinetic energy. Derive the formula KE = ½mv2.
3 Marks
4
A stone of mass 10 kg is thrown vertically upward at 40 m/s. At what height are the potential energy and kinetic energy equal? (g = 10 m/s²)
3 Marks
5
Explain the law of conservation of energy using the example of a freely falling ball. Show that the total mechanical energy remains constant at every point.
3 Marks
6
A person of mass 50 kg climbs stairs of height 5 m in 4 s. Calculate: (a) work done, (b) power developed. (g = 10 m/s²)
3 Marks
7
A car of mass 1800 kg is moving at 30 m/s when a braking force of 6000 N is applied. Find the stopping distance.
3 Marks
8
Calculate the kinetic energy of a body of mass 5 kg moving at 5 m/s. What is the kinetic energy when the speed is doubled?
2 Marks
9
Differentiate between potential energy and kinetic energy with two examples each.
2 Marks
10
A pendulum swings from side to side and eventually comes to rest. Why does it stop? Does this violate the law of conservation of energy? Explain.
2 Marks
11 Sound Waves: Characteristics and Applications 10 questions
1
Define wavelength, frequency and time period of a sound wave. What is the relation between frequency and time period?
3 Marks
2
A sound wave has a frequency of 2 kHz and wavelength 35 cm. How long will it take to travel 1.5 km?
2 Marks
3
What is meant by an echo? State the minimum distance from the reflecting surface required to produce an echo. What is the condition on the duration of the original sound?
2 Marks
4
What is SONAR? Explain how the depth of the sea can be measured using SONAR. Write the formula used.
3 Marks
5
Why do we see a lightning flash before hearing the thunder, even though both are produced simultaneously? Calculate how far a thunderstorm is if the thunder is heard 5 s after the lightning is seen. (Speed of sound = 340 m/s)
2 Marks
6
What is reverberation? How is it different from echo? How can reverberation be reduced in large auditoriums?
3 Marks
7
The speed of sound depends on which properties of the medium? How does the speed of sound vary with temperature?
2 Marks
8
Write the audible range of frequencies for human beings. What is ultrasound? Give two applications of ultrasound in medicine.
3 Marks
9
Explain how the frequency of vibration of a source affects the pitch of the sound produced. Give one example.
2 Marks
10
Compare the propagation of sound waves and light waves. Give two reasons why sound cannot travel in a vacuum.
2 Marks
12 Reproduction: How Life Continues 10 questions
1
Define health. How is being healthy different from merely being disease-free?
2 Marks
2
Distinguish between infectious and non-infectious diseases with one example each.
2 Marks
3
What is meant by immunity? How does vaccination provide immunity against a disease? Give one example of a vaccine.
3 Marks
4
Name the causative organism for the following diseases: (a) malaria, (b) tuberculosis, (c) sleeping sickness, (d) kala-azar.
2 Marks
5
What are antibiotics? How do they work against bacteria? Can they be used against viral infections? Give reasons.
3 Marks
6
Explain the statement: "Being disease-free is not the same as being healthy." Give two examples to support this statement.
3 Marks
7
List any three differences between acute and chronic diseases. Give one example of each.
3 Marks
8
How does the Aedes mosquito cause dengue? Mention two symptoms of dengue fever.
2 Marks
9
Write any three public health measures that can help in preventing infectious diseases in the community.
2 Marks
10
Why do we need to take different vaccines for different diseases even though the purpose of vaccination is the same?
2 Marks
13 Earth as a System: Energy, Matter, and Life 20 questions
1
Name the three major abiotic components of the biosphere that interact with living organisms.
1 Mark
2
Explain the carbon cycle in nature with a labelled diagram. Why is the carbon cycle important?
3 Marks
3
What is the role of the ozone layer in protecting life on Earth? How is it being depleted by human activity?
3 Marks
4
State any three consequences of soil erosion. Mention two methods to prevent soil erosion.
3 Marks
5
Distinguish between renewable and non-renewable natural resources. Give two examples of each.
2 Marks
6
Explain how the water cycle helps to maintain the water balance in nature. Name the processes involved.
3 Marks
7
Why is nitrogen important for living organisms? Briefly explain the nitrogen cycle and how nitrogen is made available to plants.
3 Marks
8
How does the excess release of carbon dioxide affect climate? What are the consequences of global warming?
2 Marks
9
What are the effects of acid rain on (a) aquatic life, (b) monuments, (c) soil fertility?
2 Marks
10
What is a biogeochemical cycle? Why are these cycles important for maintaining life on Earth? Give one example.
2 Marks
11
Define the term 'hybridisation' in the context of crop improvement. Give one example where hybridisation has been used.
2 Marks
12
What is crop rotation? Give two advantages of practising crop rotation in farming.
2 Marks
13
Distinguish between manure and chemical fertilizer. Which is considered more environment-friendly and why?
3 Marks
14
Name any four biotic and two abiotic factors that cause crop losses. What are the different methods of crop protection management?
3 Marks
15
What is composite fish culture? Name any three fish species used in a composite fish culture system and state the advantage of this system.
3 Marks
16
What are the advantages of intercropping over conventional monoculture farming? How is intercropping different from mixed cropping?
2 Marks
17
Define the following: (a) capture fishing, (b) mariculture, (c) aquaculture.
3 Marks
18
Name the three macronutrients required by plants. What is the role of each nutrient in plant growth? Name one deficiency symptom for each.
3 Marks
19
What is organic farming? State two advantages of organic farming over conventional farming that uses synthetic pesticides and fertilizers.
2 Marks
20
What is meant by genetic improvement of cattle? Give one example of a cross-breed that has improved milk production in India.
3 Marks