CBSE Class 10 Science 2025
352 questions · 716 marks · every one with the board’s own marking-scheme answer.
What 2025 actually asked, chapter by chapter
Marks we counted in the 2025 papers themselves. CBSE allocates marks per unit, not per chapter — this is what was observed, not an official CBSE weightage.
| Chapter | Marks | Share |
|---|---|---|
| Life Processes41 questions | 76 | 10.6% |
| Electricity35 questions | 73 | 10.2% |
| Metals and Non-metals34 questions | 66 | 9.2% |
| Light - Reflection and Refraction28 questions | 66 | 9.2% |
| How do Organisms Reproduce?27 questions | 63 | 8.8% |
| Magnetic Effects of Electric Current23 questions | 60 | 8.4% |
| Control and Coordination24 questions | 51 | 7.1% |
| Acids, Bases and Salts28 questions | 49 | 6.8% |
| Chemical Reactions and Equations27 questions | 47 | 6.6% |
| Heredity22 questions | 47 | 6.6% |
| The Human Eye and the Colourful World25 questions | 46 | 6.4% |
| Our Environment24 questions | 38 | 5.3% |
| Carbon and its Compounds13 questions | 33 | 4.6% |
| Periodic Classification of Elements1 question | 1 | 0.1% |
All 352 questions from 2025
- Q1Example of thermal decomposition reaction are (i) 2 AgCl → 2 Ag+Cl 2 (ii) CaCO 3 → CaO+CO 2 (iii) 2 H 2 O → 2 H 2+O 2…1 mk
- Q1In the following experimental setup of electrolysis of water, if P and Q are the gases collected in the test tubes…1 mkasked 2×
- Q1The main observations while performing the experiment of burning magnesium ribbon in air are: (i) Magnesium ribbon…1 mkasked 3×
- Q1In the electrolysis of water, the mass ratio of hydrogen and oxygen gases liberated at the electrodes is:1 mk
- Q1In which one of the following situations a chemical reaction does not occur?1 mkasked 3×
- Q1Electrolysis of water is a decomposition reaction. The mass ratio (M H: M O) of hydrogen and oxygen gases liberated at…1 mkasked 3×
- Q1Consider the following chemical equation: pAl+q H 2 O → rAl 2 O 3+s H 2 To balance this chemical equation, the values…1 mkasked 3×
- Q2A metal, M, displaces iron from aqueous solution of ferrous sulphate but fails to do so in case of aqueous solution of…1 mkasked 3×
- Q2Which of the given option represents a family of salts?1 mkasked 3×
- Q2In order to prepare dry hydrogen chloride gas in humid atmosphere the gas produced is passed through a guard tube…1 mkasked 3×
- Q2The products formed when Aluminium and Magnesium are burnt in the presence of air respectively are:1 mkasked 3×
- Q2The formula of washing soda is1 mk
- Q2You have three aqueous solutions A, B and C as given below: A - Potassium nitrate B - Ammonium chloride C - Sodium…1 mkasked 2×
- Q2The warning sign shown in the given figure must invariably be displayed/pasted on the containers which contain…1 mkasked 3×
- Q3An element 'M' has 25\% of the electrons filled in the third shell as in the second shell. The element ' M ' is:1 mk
- Q3A few pieces of granulated zinc are taken in a test tube and 2 mL of sodium hydroxide solution is added to it. When the…1 mk
- Q3Which one of the following metals is protected from corrosion by a layer of its own oxide?1 mk
- Q3The property by virtue of which a solid material can be drawn into thin wires is called:1 mkasked 2×
- Q3Select from the following a statement which is not true about burning of magnesium ribbon in air:1 mkasked 2×
- Q3In one formula unit of salt 'X', seven molecules of water of crystallisation are present. The salt 'X' is:1 mk
- Q3The following table shows the pH values of four solutions A, B, C and D on a pH scale: The solutions A, B, C and D…1 mk
- Q3The chlorine produced during the electrolysis of brine solution is used in the manufacture of:1 mk
- Q3The most common method of extraction of metals from their oxide ores is:1 mkasked 2×
- Q3A common feature observed in the crystals of washing soda, copper sulphate, gypsum and ferrous sulphate is that all1 mk
- Q3The body of human beings works within the pH range of:1 mkasked 2×
- Q4Consider the following reactions: (i) Dilute hydrochloric acid reacts with sodium hydroxide. (ii) Magnesium oxide…1 mkasked 3×
- Q4Select from the following a hydrocarbon having one C-C bond and one C ≡ C bond:1 mkasked 3×
- Q4Given below are the structures of some hydrocarbons. Select the two structures which are related to each other from the…1 mkasked 3×
- Q4A metal, 'X', on treatment with sodium hydroxide liberates a gas 'G'. It also liberates the same gas, 'G' on treatment…1 mkasked 3×
- Q4Study the following cases: (i) CuSO 4+Mg → (ii) FeSO 4+Pb → (iii) CaSO 4+Al → (iv) ZnSO 4+Ca → The case/cases in which…1 mk
- Q4Aluminium powder is used in thermit welding because:1 mkasked 3×
- Q4A Hydrocarbon which does not belong to the same homologous series of carbon compounds is1 mkasked 3×
- Q5Two metals zinc and tin are dissolved separately in definite proportions in molten copper (the primary metal) to obtain…1 mkasked 3×
- Q5The colour of the solution observed after about 1 hour of placing iron nails in copper sulphate solution is1 mkasked 3×
- Q5When a mixture of baking soda and tartaric acid is heated (or mixed in water) a product 'X' is formed, which is…1 mk
- Q5Reaction between two elements A and B, forms a compound C. A loses electrons and B gains electrons. Which one of the…1 mkasked 3×
- Q5Tooth enamel is made up of calcium hydroxyapatite (a crystalline form of calcium phosphate). This chemical starts…1 mk
- Q5Choose the incorrect statement about the common reaction used in hydrogenation of vegetable oils.1 mkasked 3×
- Q5The values of a, b, c and d in the following balanced chemical equation are respectively: a Pb(NO 3) 2 heat b PbO+c NO…1 mkasked 3×
- Q5The essential element taken up from the soil by the plants to synthesize proteins is:1 mkasked 3×
- Q6During electrolytic refining of copper, the anode, the cathode and the electrolyte used respectively are1 mkasked 3×
- Q6Select TRUE statements about lymph from the following: A. Lymph vessels carry lymph through the body and finally open…1 mkasked 3×
- Q6Juice of tamarind turns blue litmus to red. It is because of the presence of a chemical compound called1 mkasked 2×
- Q6Match Column-I with Column-II and select the correct option from the choices provided.1 mkasked 3×
- Q6The essential element used in the synthesis of proteins is:1 mk
- Q6The metals obtained from their molten chlorides by the process of electrolytic reduction are:1 mkasked 3×
- Q6Select the correct option from the following statements about the functioning of the human heart.1 mk
- Q6The opening and closing of stomata is regulated by:1 mk
- Q6The nature of aqueous solution of potassium nitrate is:1 mk
- Q7The part of the brain which maintains the posture and balance of the body is:1 mk
- Q7One-cell thick blood vessels are known as:1 mkasked 3×
- Q7The part of the hind-brain controlling involuntary actions such as salivation and vomiting in humans is:1 mk
- Q7The formation of magnesium oxide is correctly shown in option:1 mkasked 2×
- Q7Plants like rose and banana have lost the capacity to produce:1 mkasked 3×
- Q7The water of crystallization is present in (i) Bleaching Powder (ii) Plaster of Paris (iii) Washing Soda (iv) Baking…1 mkasked 3×
- Q7The growth of the pollen tubes towards ovules is an example of:1 mk
- Q8Secretion of less saliva in mouth will effect the conversion of:1 mkasked 3×
- Q8Listed below are the steps of nutrition in Amoeba. Select the correct sequence of these steps: (i) Diffusion of simple…1 mkasked 3×
- Q8A tall pea plant with round seeds (TTRR) is crossed with a short pea plant with wrinkled seeds (ttrr). The F 1…1 mkasked 2×
- Q8Mendel obtained F 2 generation by1 mk
- Q8The plant hormone present in greater concentration in the areas of rapidly dividing cells is:1 mkasked 3×
- Q8Which one of the following has half the number of chromosomes and half the amount of DNA as compared to the…1 mk
- Q8Electrical impulse travels in a neuron from1 mk
- Q8Observe the given figures A and B. When chhui-mui (sensitive) plant is touched, its leaves fold. This is due to: Figure…1 mkasked 3×
- Q8In a bisexual flower the male gametes are present in the:1 mkasked 2×
- Q9The plant hormone whose concentration stimulates the cells to grow longer on the side of the shoot which is away from…1 mkasked 3×
- Q9Select a pair of bisexual flowers from the following:1 mkasked 3×
- Q9Which among the following is not a neural action controlled by the part of human brain labelled 'X' in the figure above?1 mkasked 3×
- Q9Which one of the following statements is not correct for the plants raised by vegetative propagation?1 mk
- Q9Bryophyllum produces new plant through:1 mk
- Q9A pair of endocrine glands located in the human brain is1 mkasked 2×
- Q9Which of the following is the correct sequence of parts of female reproductive system of flowering plants in terms of…1 mk
- Q9When a pure-tall pea plant is crossed with a pure-dwarf pea plant, the percentage of tall pea plants in F 1 and F 2…1 mkasked 3×
- Q10Parasitic mode of nutrition is observed in:1 mk
- Q10Select the option having correct matching of the organism given in Column I with the mode of reproduction in Column II:…1 mk
- Q10To get an image of magnification -1 on a screen using a lens of focal length 20 cm, the object distance must be:1 mkasked 3×
- Q10When a seed germinates the root grows downwards and a small shoot grows upward. This shoot is known as1 mk
- Q10Temporary finger-like extensions on the cell surface to take in food is formed in:1 mk
- Q10The correct/true statement(s) for a bisexual flower is/are: (i) They possess both stamen and pistil. (ii) They possess…1 mkasked 3×
- Q10The gastric glands present in the wall of the stomach release:1 mk
- Q10The modes of reproduction in Spirogyra and Planaria respectively are1 mkasked 3×
- Q10The number of chromosomes in a cell division is halved. This kind of cell division is observed in:1 mkasked 3×
- Q11Which one of the following is not an excretory product in plants?1 mk
- Q11The plant hormones promoting rapid cell division in seeds and wilting of leaves respectively are1 mkasked 3×
- Q11An optical device 'X' is placed obliquely in the path of a narrow parallel beam of light. If the emergent beam gets…1 mkasked 3×
- Q11The basic filtration unit of the excretory system in human beings is:1 mkasked 3×
- Q11If pea plants with round and green seeds (RRyy) are crossed with pea plants having wrinkled and yellow seeds (rrYY),…1 mkasked 3×
- Q12In human alimentary canal, the digestive juice secreted by the gastric glands are1 mkasked 3×
- Q12A piece of wire of resistance 'R' is cut lengthwise into three identical parts. These parts are then connected in…1 mkasked 3×
- Q12An object is placed at a distance of 30 cm from the pole of a concave mirror. If its real and inverted image is formed…1 mkasked 3×
- Q12Select the correct statement from the following:1 mk
- Q12In aerobic respiration, the steps are: breakdown of glucose to pyruvate and its further conversion to carbon dioxide.…1 mkasked 3×
- Q12When a beam of white light passes through a region of very fine dust particles, the colour of light that scatters the…1 mkasked 2×
- Q12The breakdown of glucose has taken the following pathway: Glucose Pyruvate + Energy Lactic acid + Energy The sites 'a'…1 mkasked 3×
- Q13The curvature of eye lens of human eye1 mk
- Q13In the human eye, most of the refraction for the light rays entering the eye occurs at the surface of:1 mk
- Q13The part of the human eye which can modify the curvature of the eye lens to some extent is:1 mk
- Q13In order to obtain large images of the teeth of patients, the dentist holds the concave mirror in such a manner that…1 mkasked 3×
- Q13Identify from the following the ray diagram which shows the correct path of the reflected ray for the ray incident on a…1 mkasked 3×
- Q13Mirror 'X' is used to concentrate sunlight in solar furnace and Mirror 'Y' is fitted on the side of the vehicle to see…1 mkasked 3×
- Q13The white light entering a glass prism, gets split into its constituent colours. It is observed that:1 mk
- Q13A wire of length ' l ' is gradually stretched so that its length increases to 3 l. If its original resistance is R,…1 mkasked 2×
- Q13In the given figure the angle of incidence and the angle of deviation respectively are:1 mk
- Q13An electric bulb is rated 220 V; 11 W. The resistance of its filament when it glows with a power supply of 220 V is:1 mkasked 3×
- Q13In domestic electric circuits, the colour of insulation covers of wires in the cables of electric iron/electric toaster…1 mk
- Q14The possible way to restore clear vision of those people whose eyeball has elongated is the use of suitable1 mk
- Q14The minimum number of identical bulbs of rating 4V; 6W, that can work safely with desired brightness, when connected in…1 mkasked 3×
- Q14Most of the refraction for the light rays entering the eye occurs at1 mk
- Q14Which one of the following statements is not true about a bar magnet?1 mkasked 3×
- Q14The part of human eye which controls the amount of light entering into it.1 mk
- Q14An old person is suffering from an eye defect caused by weakening of ciliary muscles and diminishing flexibility of the…1 mk
- Q14The resistivity of a wire made of an alloy is generally:1 mk
- Q14An electric bulb is connected to a power supply of 220 V. If the current drawn by the bulb from the supply is 500 mA,…1 mkasked 2×
- Q14A boy while reading a book, keeps it much beyond 25 cm from his eyes. This defect of vision has arised because of1 mk
- Q15Four identical resistors of 12 Ω each are connected in series to form a square ABCD as shown in the figure. The…1 mkasked 3×
- Q15The examples of natural and manmade (artificial) ecosystems are respectively1 mkasked 3×
- Q15Consider the following ray diagram: Here, the angle of incidence and angle of deviation respectively are1 mk
- Q15Which of the following groups do not constitute a food chain? (i) Wolf, rabbit, grass, lion (ii) Plankton, man,…1 mkasked 3×
- Q15The phenomenon responsible for making the smoke particles visible when a beam of sunlight enters a smoke filled room…1 mk
- Q15In the following groups of wastes, which group contains only non- biodegradable wastes?1 mk
- Q15Consider the following food chain: Grass → Grasshopper → Frog → Snake → Eagle If the amount of energy available at…1 mkasked 2×
- Q15In the food chains given below. Select the most efficient food chain in terms of energy:1 mkasked 3×
- Q15The strength of magnetic field produced inside a long straight current carrying solenoid does not depend upon:1 mkasked 2×
- Q15The strength of the magnetic field produced inside a current carrying long straight solenoid does not depend upon:1 mk
- Q16Other than the abiotic components, which of the given biotic components are not required to make an aquarium with small…1 mkasked 3×
- Q16Which one of the following gets biomagnified at different levels in a food chain?1 mkasked 3×
- Q16Identify from the following a group containing all non-biodegradable substances.1 mkasked 3×
- Q16The incorrect statement about ozone is1 mkasked 2×
- Q16Green plants occupy the first trophic level in every food chain because they1 mk
- Q16Human activities that are affecting the environment are:1 mkasked 3×
- Q16The percentage of solar energy which is not converted into food energy by the leaves of green plants in a terrestrial…1 mkasked 3×
- Q17Assertion: Propanal and propanone are structural isomers. Reason (R): Propanal and propanone both have the same…1 mk
- Q17Assertion: Carbon and its compounds are our major sources of fuels. Reason (R): Most of the carbon compounds on burning…1 mkasked 3×
- Q17Assertion: All exothermic reactions are accompanied with evolution of heat and light. Reason (R): Combination reactions…1 mk
- Q17Assertion: Ductility is that property of metals which enables copper to be used in making cooking utensils. Reason (R):…1 mk
- Q17Assertion: Silver chloride turns grey in sunlight. Reason (R): Decomposition of silver chloride into silver and…1 mkasked 3×
- Q17Assertion: In large animals, oxygen can reach different parts of the animal's body easily. Reason (R): Respiratory…1 mkasked 2×
- Q17Assertion: Decomposition reactions are generally endothermic reactions. Reason (R): Decomposition of organic matter…1 mkasked 3×
- Q17Assertion: The metals high up in the reactivity series cannot be obtained from their compounds by heating with carbon.…1 mk
- Q17Assertion: Brass is prepared by first melting copper and then dissolving tin into it in a definite proportion. Reason…1 mk
- Q17Assertion: Hydrogen gas is not evolved when a metal reacts with nitric acid. Reason (R): Nitric acid is a strong…1 mkasked 2×
- Q18Assertion: Concentrated nitric acid is diluted by adding water slowly to acid with constant stirring. Reason (R):…1 mkasked 3×
- Q18Assertion: In our actions of writing or talking, our nervous system communicates with the muscles. Reason (R): Cranial…1 mkasked 3×
- Q18Assertion: A mango seed will germinate to form a mango tree. Reason (R): Heredity determines the process by which…1 mkasked 3×
- Q18Assertion: Xylem tissue moves water and minerals obtained from the soil by the roots. Reason (R): Xylem tissue is found…1 mkasked 3×
- Q18Assertion: A human child bears all the basic features of human beings. Reason (R): It looks exactly like its parents,…1 mkasked 3×
- Q18Assertion: The embryo gets nutrition from the mother's blood with the help of a special tissue called placenta. Reason…1 mkasked 3×
- Q19Assertion: The bending of a wire in the form of a coil of several turns does not affect its electrical resistance.…1 mk
- Q19Assertion: In reptiles, the temperature at which the fertilized eggs are kept decides the sex of the offsprings. Reason…1 mkasked 3×
- Q19Assertion: The pattern of the magnetic field of a solenoid carrying a current is similar to that of a bar magnet.…1 mkasked 3×
- Q19Assertion: Nichrome is an alloy which is commonly used in electrical heating devices such as electric irons, toasters,…1 mkasked 2×
- Q19Assertion: Magnetic field lines around a bar magnet never intersect each other. Reason (R): Magnetic field produced by…1 mkasked 3×
- Q19Assertion: In the common domestic circuits the earth wire is connected to a metallic plate buried deep inside the…1 mkasked 3×
- Q19Assertion: No two magnetic field lines are found to cross each other. Reason (R): The compass needle cannot point…1 mkasked 3×
- Q20Assertion: The amount of ozone in the atmosphere began to drop sharply in the 1980s. Reason (R): The oxygen atoms…1 mkasked 3×
- Q20Assertion: When ciliary muscles contract, eye lens becomes thin. Reason (R): Ciliary muscles control the power of the…1 mkasked 2×
- Q20Assertion: Use of jute bags for shopping reduces pollution. Reason (R): Jute is biodegradable and its bag may be reused…1 mkasked 3×
- Q20Assertion: Animals will not get energy if they eat (consume) coal as food. Reason (R): Specific enzymes are needed for…1 mkasked 3×
- Q20Assertion: Food web is a network of several food chains operating in an ecosystem. Reason (R): Food web decreases the…1 mkasked 3×
- Q20Assertion: White light is dispersed by a glass prism into seven colours. Reason (R): The red light bends the least…1 mk
- Q20Assertion: All organisms can make organic compounds like sugar and starch from inorganic substances using radiant…1 mkasked 3×
- Q21Cinnabar is an ore of a metal 'X'. When this ore is heated in air, it is first converted into oxide of 'X' (XO) and…2 mk
- Q21While burning a magnesium ribbon in air, list two safety measures which should be followed. Also state two observations…2 mk
- Q21Name the compound used in black and white photography. State whether the reaction that occurs is exothermic or…2 mk
- Q21A light green coloured solution of sulphate salt of metal 'P' is taken in a beaker, a rod of another metal "Q" is put…2 mk
- Q21Balance the following chemical equations: CO 2+H 2 O [ Chlorophyll ] Sunlight C 6 H 12 O 6+O 2+H 2 O Pb(NO 3) 2 Heat…2 mk
- Q21A student performs the following experiment in his school laboratory. List two observations to justify that in this…2 mkasked 2×
- Q21Define oxidation. Identify and name the substance oxidised in the following reaction: CuO+H 2 → Cu+H 2 O2 mk
- Q21A crystalline substance of green colour 'X' emits gases of characteristic odour when heated over a flame. It first…2 mk
- Q21List the possible sources of energy required in decomposition reactions. Illustrate any one with a suitable example. OR…2 mkasked 3×
- Q21An object is placed at a distance of 10 cm in front of a concave mirror of focal length 15 cm. Use mirror formula to…2 mk
- Q21Name a metal found in the earth's crust (i) in free state and (ii) in the form of its compound. State where each of…2 mk
- Q21During an experiment, a student observes that the given mirror is forming an erect and diminished image for all…2 mk
- Q21In common practice silver is recovered from silver nitrate solution by the use of copper metal. Name the type of…2 mkasked 2×
- Q21A gas 'X' is found in the upper layer of atmosphere. It is a deadly poison, but still essential for all life forms on…2 mk
- Q22Consider two lamps A and B of rating 50 W; 220 V and 25 W; 220 V respectively. Find the ratio of the resistances of the…2 mk
- Q22How is brain protected in our body? A doctor finds in one of his patients that he is not maintaining a proper posture…2 mkasked 3×
- Q22What are micelles? Draw the structure.2 mk
- Q22Determine the maximum and minimum resistance which can be obtained by joining five resistors of 1/5 Ω each. OR…2 mk
- Q22Write the formula of the ions which (i) acids, and (ii) bases generate in water solutions. Dry HCl gas does not change…2 mk
- Q22A chemical compound 'X' is used to bleach washed clothes in laundry as well as to make drinking water free from germs.…2 mk
- Q22Use Ohm's law to determine the potential difference across the 6 Ω resistor in the following circuit when key is…2 mk
- Q22Draw labelled diagrams to show different stages of budding in Hydra.2 mkasked 3×
- Q22Show the formation of magnesium chloride by electron transfer. Write the name of the cation and anion present in the…2 mkasked 2×
- Q22Consider the following circuits: (i) (ii) (iii) In which circuit will the power dissipated in the circuit be (I)…2 mk
- Q22Giving reason, state the advantage of using baking powder over baking soda for the preparation of bread or cakes.2 mk
- Q22Give reasons: The male reproductive organ responsible for formation of germ cells is located outside the abdominal…2 mkasked 3×
- Q22Select from the following the members of same homologous series: (1) (2) (3) (4) What happens to (i) the melting point,…2 mkasked 2×
- Q23State the main function of veins in human circulatory system. Why do they not need thick walls?2 mkasked 2×
- Q23Name the tissues which form the vascular bundle. State their function in plants.2 mk
- Q23When an incident ray of light enters a medium 'X' from air, it bends towards the normal. Infer about the following with…2 mk
- Q23How is lymph formed? State its important function. OR Identify 'X' in the figure of human nephron shown below. What…2 mkasked 3×
- Q23Besides minimising the loss of blood, why is it essential to plug any leak in a blood vessel? Name the component of…2 mkasked 3×
- Q23An object is placed at a distance of 30 cm in front of a concave mirror of focal length 20 cm. Use mirror formula to…2 mk
- Q23Name the parts of hind-brain of the human brain. Which part of the hind-brain controls involuntary actions such as…2 mk
- Q23"Proteins control the expression of various characters." Explain this statement by taking an example of "tallness" as a…2 mkasked 3×
- Q23A person is making a list to purchase few things from a nearby market. Explain how the fore-brain plays an important…2 mk
- Q23"In human alimentary canal the small intestine is designed to absorb the digested food." Justify this statement.2 mk
- Q23Study the given diagram and write the type of movement exhibited by: Root, and Shoot, mentioning the stimulus in each…2 mk
- Q23"Plants use a variety of techniques to get rid of waste material." Justify this statement giving any four ways.2 mk
- Q23State the main function of arteries. Why do they have thick and elastic walls?2 mk
- Q24Explain how the proteins control the 'characteristics' in an organism with the help of an example of 'short height'…2 mk
- Q24An object is placed at a distance of 60 cm from a concave lens of focal length 30 cm. Use lens formula to find the…2 mk
- Q24Study the figure in which the path of a ray of light going from Medium 1 to Medium 2 is shown. Out of the two Media -…2 mkasked 3×
- Q24Write one function each of the following, in a seed: (i) Seed coat (ii) Cotyledon (iii) Radicle (iv) Plumule OR Write…2 mkasked 3×
- Q24Explain with the help of a flow chart that in human beings father is responsible for the sex (male or female) of the…2 mkasked 2×
- Q24The values of absolute refractive indices of kerosene and water are 1.44 and 1.33 respectively. Compare the two media…2 mk
- Q24"Sex of the children is determined by type of sex chromosome which they inherit from their father." Justify the…2 mk
- Q24Pure-tall (TT) pea plants are crossed with pure-dwarf (tt) pea plants. The pea plants obtained in F 1 generation are…2 mk
- Q24Explain how the proteins control the 'characteristics' in an organism with the help of an example of 'tallness' trait…2 mk
- Q25Give reasons: (i) The sky appears dark to passengers flying at very high altitude. (ii) 'Danger' signal lights are red…2 mkasked 3×
- Q25A wire of resistance R is cut into three equal parts. If these three parts are then joined in parallel, calculate the…2 mk
- Q25Out of the two lenses, one concave and the other convex, state which one will diverge a parallel beam of light falling…2 mkasked 3×
- Q25Study the food web given below: Identify the food chain(s) in which the eagle receives the highest energy from the…2 mk
- Q25A student has difficulty in reading his textbooks but can read the blackboard clearly while sitting in the last row.…2 mkasked 3×
- Q25Draw a ray diagram to show the refraction of a ray of light passing through an equilateral glass prism. Mark the angle…2 mkasked 3×
- Q25State two applications of Joule's heating in domestic electric circuit. Establish the relationship between the…2 mk
- Q26Why are the organisms of first trophic level important in any food chain? Justify the following statement: 'The flow of…2 mk
- Q26"Excessive use of chemicals and pesticides in agriculture adversely effect the environment." Justify this statement.2 mkasked 2×
- Q26State the role of an electric fuse, used in series with an electrical appliance. Why should in an electric circuit a…2 mk
- Q26A copper wire on burning in flame, gets coated with a black substance. Write the chemical equation of the reaction that…2 mk
- Q26Write the percentage of the energy of sunlight captured by green plants, to convert it into food energy. Explain the…2 mk
- Q26What happens when: (write balanced chemical equation) Lead nitrate is thermally decomposed, Natural gas burns in oxygen…2 mk
- Q26How and why is an electric fuse used in an electric circuit? Briefly describe its function.2 mk
- Q26Draw the pattern of magnetic field lines due to a current carrying straight conductor. Mark on it the direction of…2 mk
- Q26Four resistors, each of resistance 2 · 0 Ω, are joined end to end to form a square ABCD as shown. Using appropriate…2 mk
- Q26Translate the following statements into chemical equations and then balance them: Nitric acid reacts with calcium…2 mk
- Q26An electric kettle is rated 750 W; 220 V. Can this kettle be used in a circuit which has a fuse of current rating 3 A?…2 mk
- Q26Indicate the flow of energy in a food chain operating in an ecosystem. Why is it uni-directional? Give reason.2 mk
- Q26What are magnetic field lines. List two important properties of magnetic field lines.2 mk
- Q26We do not clean natural ponds or lakes whereas an aquarium or a swimming pool needs to be cleaned regularly. Why?2 mk
- Q26Write chemical equation for the chemical reaction between the aqueous solutions of sodium sulphate and barium chloride.…2 mk
- Q26A voltage source sends a current of 2 A to a resistor of 40 Ω connected across it for 5 minutes. Calculate the…2 mk
- Q26An electric kettle is rated 230 V; 1000 W. Calculate the resistance of its heating element when in operation.2 mk
- Q26An electric fuse is rated 8 A. Can it be used with an electrical appliance of rating 5 kW, 200 V? Justify your answer.2 mk
- Q27Why do we balance a chemical equation? Name and state the law that suggests the balancing of a chemical equation?…3 mkasked 3×
- Q27State the change that is observed when a China dish containing copper powder is heated over the flame of a burner. Name…3 mk
- Q27Write balanced chemical equation for the reactions that occur when steam is passed over red hot iron. natural gas is…3 mkasked 2×
- Q27"Displacement reactions also play a key role in extracting metals in the middle of the reactivity series." Justify this…3 mkasked 3×
- Q27How is a double displacement reaction different from a displacement reaction? Explain giving example in the form of…3 mk
- Q27Define one ampere. The resistance of a wire of 0.01 cm radius is 14 Ω. If the resistivity of the material of the wire…3 mk
- Q27What is short circuiting? State its possible causes. What is likely to happen if a domestic circuit gets short…3 mk
- Q27Write chemical formula of washing soda. How is it obtained from baking soda? List two uses of washing soda.3 mkasked 3×
- Q27Answer the following questions for a case in which a current carrying conductor is placed in a uniform magnetic field:…3 mk
- Q27Explain why respiration is considered as an exothermic reaction. Give the chemical equation for this reaction.3 mk
- Q27Define one volt potential difference between two points in an electric field. Draw a schematic diagram of an electric…3 mk
- Q27What is a reactivity series of elements? How is it developed? Arrange the following elements as they are arranged in…3 mk
- Q27(i) Define the term decomposition reaction. Write one chemical equation each for decomposition reaction where energy is…3 mkasked 3×
- Q28Two substances 'A' and 'B' are burnt in air separately. For 'A', ashes are collected and dissolved in water to get…3 mk
- Q28Study the experimental set-up given in the figure and answer the following questions: Identify these metals from the…3 mk
- Q28Name and describe the most widely used method for refining impure metals?3 mk
- Q28In an experiment a student dipped pH papers in four different solutions A, B, C and D and reported his observation as…3 mk
- Q28Design an activity to show that metals are good conductors of heat and have high melting points.3 mk
- Q28Common salt is an important raw material for various chemicals of daily use. State in brief the method of preparation…3 mkasked 3×
- Q28Samples of four metals A, B, C and D were added one by one to the following solutions. The results obtained were…3 mk
- Q28With the help of an activity, explain the conditions under which iron articles get rusted. OR (i) Name two metals which…3 mkasked 3×
- Q28Write the electron-dot structures of (i) sodium, and (ii) oxygen. Using these structures, show the formation of sodium…3 mk
- Q28Observe the following diagram showing an experiment to determine the conditions under which a metal ' M ' corrodes.…3 mkasked 3×
- Q28State the chemical property in each case on which the following uses of baking soda are based upon: (i) as an…3 mkasked 2×
- Q29An object of size 5 cm is placed at a distance of 30 cm from the optical centre of a converging lens of focal length 20…3 mk
- Q29Name the blood vessel that brings (i) oxygenated blood (ii) deoxygenated blood, to the human heart. Also name that…3 mkasked 2×
- Q29The digestion of food in human alimentary canal is a complex process. State the enzyme/salt present in the following…3 mk
- Q29What is meant by reflex arc? Where are they formed in the human body? Why have reflex arcs evolved in animals?3 mk
- Q29(i) Study the diagram and name the parts marked as A, B, C and D. (ii) Write the function of A and C.3 mk
- Q29Define hormone. "Hormones should be secreted in precise quantities. We have a feedback mechanism through which this is…3 mkasked 2×
- Q29Write the name and one function of respiratory pigment found in human beings. Why do lungs always contain a residual…3 mk
- Q29What is the first step of cellular respiration? In which part of the cell does it occur? Write the equation for the…3 mk
- Q29Why is blood circulation in vertebrates known as "double circulation"? Trace its path in the form of a flow chart.3 mk
- Q29On the basis of the characteristics of the processes given in the brackets in each case, differentiate between the…3 mk
- Q29Enlist any two nitrogenous waste products removed from the blood of human kidney. Name the capillary cluster formed by…3 mk
- Q30Differentiate between self-pollination and cross pollination. Which one of the two is better for the survival of…3 mk
- Q30"In human beings the genes inherited from the parents decide whether the newborn individual is male or female." Explain…3 mk
- Q30Define fertilisation. What happens to Zygote, Ovule, Ovary and Stamens after fertilisation in a flowering plant?3 mk
- Q30A pure pea plant bearing terminal flowers was cross-pollinated with a pure plant having axillary flowers. In F 1…3 mk
- Q30The lowest part of the ear called earlobe, is closely attached to the side of the head in some of us (Figure 'X'), and…3 mkasked 2×
- Q30A pure pea plant having round (R), yellow (Y) seeds is crossed with another pure pea plant having wrinkled (r), green…3 mkasked 3×
- Q30How many chromosomes are present in human beings? Out of these how many are sex chromosomes? Explain how, in sexually…3 mk
- Q30What are chromosomes? Explain in brief how stability of DNA content of a species is ensured in sexually reproducing…3 mk
- Q30State two limitations of electrical impulses in multicellular organisms. Why is chemical communication better than…3 mkasked 3×
- Q30The gene combination of purple flowered pea plants is denoted as (WW) and that of white flowered pea plants as (ww),…3 mkasked 2×
- Q31Draw ray diagrams to show the nature, position and relative size of the image formed by a convex mirror when the object…3 mkasked 3×
- Q31If we want to obtain a real and magnified image of an object by using a concave mirror of focal length 18 cm. Where…3 mk
- Q31A person is suffering from an eye defect in which the far point of the eye is much nearer than infinity. Name the…3 mk
- Q31If we want to obtain a virtual and magnified image of an object by using a concave mirror of focal length 18 cm, where…3 mkasked 2×
- Q31The power of a lens is -0.25 D. Based on this information, find out The type of lens and its focal length. The eye…3 mkasked 3×
- Q31A convex lens forms an 8.0 cm long image of a 2.0 cm long object which is kept at a distance of 6.0 cm from the optical…3 mk
- Q31An object is placed at a distance of 20 cm from the optical centre of a concave lens and its image is formed on the…3 mk
- Q31List three raw materials required by terrestrial plants for photosynthesis. Explain how nature provides these raw…3 mk
- Q31What is a rainbow? Draw a labelled diagram to show its formation.3 mk
- Q31A hormone 'X' is secreted in blood when a person is under scary situation. Identify the hormone 'X' and the gland that…3 mk
- Q31A convex mirror used for rear view on an automobile has a focal length of 1.5 m. If a 3 m high bus is located at 6.0 m…3 mk
- Q31A person has to keep reading material much beyond 25 cm (say at 50 cm) from the eye for comfortable reading. Name the…3 mk
- Q31A student placed a candle flame at different distances from a convex lens and focused its image on a screen. He…3 mkasked 3×
- Q32The resistance of a wire of 0.01 cm radius is 7 ohms. If the resistivity of the material of the wire is 44 × 10^-6 ohm…3 mkasked 3×
- Q32The electrical resistivity of three materials A, B and C at 20°C is given below: (i) Classify these materials as…3 mkasked 2×
- Q32Consider the following electric circuit: Calculate the values of the following: The total resistance of the circuit The…3 mkasked 3×
- Q32Resistance of a wire of length 1 m is 35 Ω at 20°C. If the diameter of the wire is 0.2 mm, determine the resistivity of…3 mk
- Q32Draw a labelled diagram to show the pattern of magnetic field lines on a horizontal white board due to a straight…3 mk
- Q32Differentiate between a gamete and a zygote. State their significance in sexual reproduction.3 mk
- Q32Define the term "potential difference" between two points in an electric circuit carrying current. Name and define its…3 mk
- Q32In one of Mendalian experiments, when F 1 generation pea plants with round yellow seeds were self-pollinated, pea seeds…3 mk
- Q32Name and state the rule which determines the force on a current carrying conductor placed in a uniform magnetic field.…3 mk
- Q32Consider a rectangular cardboard having two holes P and Q through which a current carrying circular loop has been…3 mk
- Q32A person uses lenses of +2.0 D power in his spectacles for the correction of his vision. Name the defect of vision the…3 mkasked 2×
- Q32Three resistors of 2 Ω, 3 Ω and 6 Ω are connected in (i) series, and (ii) parallel. Draw the arrangements of the…3 mkasked 2×
- Q33Write the relationship between resistivity and resistance of a cylindrical conductor of length l and area of…3 mk
- Q33Draw a diagram to show the dispersion of white light by a glass prism. What is spectrum? Give reason for its formation.3 mk
- Q33Explain the statement "Potential difference between two points is 1 volt". What do the symbols given below represent in…3 mkasked 3×
- Q33Name the glands that secrete: (i) Adrenaline (ii) Thyroxin Explain with example how the timing and amount of hormone…3 mk
- Q33Give reasons for the following: Rate of breathing in aquatic animals is much faster than terrestrial organisms. Rings…3 mk
- Q33"The third wire of earth connection is very important in domestic electric appliances." Justify this statement. List…3 mk
- Q33Some harmful chemicals get accumulated in human bodies through the food chain. Name this phenomenon. Explain the reason…3 mk
- Q33Write the essential function performed by ozone at the higher levels of the atmosphere. How is it formed in the upper…3 mkasked 2×
- Q33"In a food chain energy flow is unidirectional." Give two reasons for the given statement. If 10,000 J energy is…3 mkasked 3×
- Q33What are decomposers? Give two examples. State how they maintain a balance in an ecosystem.3 mkasked 3×
- Q34A carbon compound 'A' on heating with excess conc. H 2 SO 4 forms a compound 'B', which on addition of one mole of…5 mkasked 2×
- Q34(i) Consider the following metals: K, Ca, Al, Cu, Ag, Fe Select from the above metals, a metal which I. does not react…5 mkasked 3×
- Q34Define the term "Functional group of a carbon compound". Write the formula of functional group present in (i) propanol…5 mk
- Q35(i) "The length of the small intestine in various animals depends on the food they eat." Justify the statement. (ii)…5 mkasked 3×
- Q35(i) What is regeneration? Give one example of an organism that shows this process and one organism that does not. Why…5 mkasked 2×
- Q35Analyse the given situations and interpret the possible reason for each: (i) Iodine deficiency in diet increases the…5 mkasked 3×
- Q35(i) Write the functions of the following parts of human female reproductive system: (I) Ovary (II) Fallopian tube (III)…5 mkasked 3×
- Q35(i) Identify the parts 'X' and 'Y' in the figure given below: (ii) Name the yellowish coloured structures produced by…5 mkasked 3×
- Q35Define Puberty. List any two changes seen in boys at the time of puberty. Why are testes in human males located outside…5 mkasked 2×
- Q35Name the parts marked as 'A' and 'B' in the given diagram. Write in detail the changes that take place in a flower when…5 mk
- Q35Name the method by which Amoeba and Leishmania reproduce. Write a major difference in the way they divide to produce…5 mk
- Q36(i) "In refraction of light through a rectangular glass slab, the emergent ray is always parallel to the direction of…5 mkasked 3×
- Q36The given figure shows the current passing through the straight conductor XY. (i) Copy the diagram and draw the…5 mkasked 3×
- Q36(i) Draw electron dot structure of chlorine molecule. ( Atomic Number of Chlorine =17) (ii) What happens when chlorine…5 mk
- Q36(i) Draw the pattern of the magnetic field lines for the two parallel straight conductors carrying current of same…5 mkasked 3×
- Q36Study the following electric circuit diagram and answer the questions that follow: (i) What does the circuit diagram…5 mk
- Q36Observe the following diagram and compare (i) speed of light and (ii) optical densities of the three media A, B and C.…5 mkasked 3×
- Q36What are magnetic field lines? How is the direction of magnetic field at a point determined? Draw the pattern of…5 mkasked 2×
- Q36(i) The power of a lens 'X' is -2•5 D. Name the lens and determine its focal length in cm. For which eye defect of…5 mkasked 3×
- Q37Acid-base indicators can be used to distinguish between an acid and a base. Universal indicator, a mixture of several…4 mkasked 3×
- Q37Seawater contains many salts dissolved in it. Common salt is separated from these salts. Deposits of solid salt are…4 mkasked 3×
- Q37The combining capacity of various elements depends on the number of valence electrons. Also the reactivity of elements…4 mkasked 3×
- Q37Many pure metals like copper, iron and gold are very soft and as such are considered unsuitable for certain uses.…4 mkasked 3×
- Q37Common salt is a very important chemical compound for our daily life. It's chemical name is sodium chloride and it is…4 mkasked 3×
- Q37'A' and 'B' are two salts used for washing purposes. Salt 'A' is used for bathing also. Four test tubes I, II, III and…4 mkasked 3×
- Q38In human beings, there are 23 pairs of chromosomes. Out of these 23 pairs of chromosomes (i.e. 46 chromosomes), 22…4 mkasked 3×
- Q38A person while climbing up a rocky hill comes into a panic state and fear. His body starts reacting in a…4 mkasked 3×
- Q38The growth movements of plant parts in which the direction of the stimulus determines the direction of the response is…4 mkasked 3×
- Q38The maintenance functions of all living organisms must go on even when they are not doing anything particular. Even…4 mkasked 3×
- Q38In life there are certain changes in the environment called 'stimuli' to which we respond appropriately. Touching a…4 mkasked 3×
- Q38When a girl is born, the ovaries already contain thousands of immature eggs. On reaching puberty, some of these start…4 mkasked 3×
- Q39A person allowed a narrow beam of white light from the sun to enter a dark room through a small aperture and placed a…4 mkasked 3×
- Q39In order to obtain magnetic field lines around a bar magnet, a student performed an experiment using a magnetic compass…4 mkasked 3×
- Q39Study the circuit shown in which two resistors X and Y of resistances 3 Ω and 6 Ω respectively are joined in series…4 mkasked 3×
- Q39In our homes, we receive the supply of electric power through a main supply also called mains, either supported through…4 mkasked 3×
- Q39As shown in the diagram, an electric circuit consisting of an ammeter, a voltmeter, 4 cells of 1 · 5 V each, a plug key…4 mkasked 3×
- Q39The students in a class took a thick sheet of cardboard and made a small hole in its centre. Sunlight was allowed to…4 mkasked 3×
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