CBSE Class 10 Science 2024
325 questions · 678 marks · 324 with the board’s own marking-scheme answer so far.
What 2024 actually asked, chapter by chapter
Marks we counted in the 2024 papers themselves. CBSE allocates marks per unit, not per chapter — this is what was observed, not an official CBSE weightage.
| Chapter | Marks | Share |
|---|---|---|
| Electricity29 questions | 70 | 10.3% |
| Life Processes31 questions | 67 | 9.9% |
| Chemical Reactions and Equations33 questions | 63 | 9.3% |
| How do Organisms Reproduce?28 questions | 62 | 9.1% |
| Metals and Non-metals26 questions | 56 | 8.3% |
| Magnetic Effects of Electric Current23 questions | 48 | 7.1% |
| Acids, Bases and Salts23 questions | 48 | 7.1% |
| Light - Reflection and Refraction17 questions | 47 | 6.9% |
| Heredity22 questions | 46 | 6.8% |
| Carbon and its Compounds21 questions | 44 | 6.5% |
| Control and Coordination20 questions | 42 | 6.2% |
| The Human Eye and the Colourful World23 questions | 40 | 5.9% |
| Our Environment20 questions | 34 | 5.0% |
All 325 questions from 2024
- Q1Zn+2 CH 3 COOH →(CH 3 COO) 2 Zn+H 2 The above reaction is a:1 mkasked 2×
- Q1Which of the following is not a thermal decomposition reaction?1 mk
- Q1An iron nail is placed in a solution of copper sulphate. The nail is taken out after 15 minutes. The nail will be found…1 mk
- Q1A chemical reaction in which exchange of ions occurs between the reactants, is known as:1 mk
- Q1Identify the product 'X' obtained in the following chemical reaction: CaCO 3 Δ^′ X^′+CO 21 mkasked 3×
- Q1To balance the following chemical equation, the values of the coefficients x, y and z must be respectively: x Zn(NO 3)…1 mkasked 2×
- Q1Solid Calcium oxide reacts vigorously with water to form Calcium hydroxide accompanied by the liberation of heat. From…1 mkasked 2×
- Q1When 2 mL of sodium hydroxide solution is added to few pieces of granulated zinc in a test tube and then warmed, the…1 mkasked 3×
- Q2Select a pair of natural indicator from the following:1 mkasked 3×
- Q2The number of shells required to write the electronic configuration of Potassium (At. No. 19)1 mk
- Q2The acid produced in our stomach during digestion and the base used to neutralise the excess acid during indigestion…1 mk
- Q2An aqueous solution of a salt turns blue litmus to red. The salt could be the one obtained by the reaction of:1 mkasked 2×
- Q2Which of the following is a redox reaction, but not a combination reaction?1 mkasked 3×
- Q2Juice of tamarind turns blue litmus to red. It is because of the presence of an acid called:1 mkasked 2×
- Q2Select from the following a decomposition reaction in which source of energy for decomposition is light:1 mkasked 3×
- Q3Select from the following a process in which a combination reaction is involved:1 mkasked 2×
- Q3Which of the following reactions is an endothermic reaction?1 mk
- Q3An aqueous solution 'A' turns phenolphthalein solution pink. When another aqueous solution 'B' is added to the pink…1 mk
- Q3A metal and a non-metal that exists in liquid state at the room temperature are respectively:1 mkasked 3×
- Q3A chemical compound used in glass, soap and paper industries is1 mkasked 3×
- Q3The salt present in tooth enamel is:1 mkasked 2×
- Q3Four solutions, namely glucose, alcohol, hydrochloric acid and sulphuric acid filled in four separate beakers are…1 mkasked 3×
- Q4The name and formula of third member of homologous series of alkyne is:1 mk
- Q4The structural formula of Cyclohexane is1 mk
- Q4An aqueous solution of sodium chloride is prepared in distilled water. The pH of this solution is:1 mkasked 3×
- Q4The oxide which can react with HC l as well as KOH to give corresponding salt and water is1 mkasked 3×
- Q4Carbon compounds: (i) are good conductors of electricity. (ii) are bad conductors of electricity. (iii) have strong…1 mkasked 2×
- Q4The metals which are found in both free state as well as combined state are:1 mkasked 3×
- Q5The number of single and double bonds present in a molecule of benzene (C 6 H 6) respectively, are:1 mkasked 3×
- Q5Which of the following is an alloy of copper and tin?1 mk
- Q5Consider the following cases: CaSO 4+Al → CuSO 4+Ca → FeSO 4+Cu → ZnSO 4+Mg → The cases in which new products will form…1 mkasked 2×
- Q5Consider the following Chemical equation: aAl 2 O 3+bHCl → cAlCl 3+d H 2 O In order to balance this chemical equation,…1 mkasked 2×
- Q5Consider the following compounds: FeSO 4; CuSO 4; CaSO 4; Na 2 CO 3 The compound having maximum number of water of…1 mkasked 3×
- Q5The products obtained when Lead nitrate is heated in a boiling tube.1 mk
- Q5A metal 'X' is used in thermit process. When 'X' is heated with oxygen, it gives an oxide 'Y', which is amphoteric in…1 mkasked 3×
- Q6Which one of the following hydrocarbons is different from the others?1 mkasked 2×
- Q6Select saponification reaction from the following:1 mk
- Q6Identify the correct statement about the following reaction: 2 H 2 S+SO 2 → 2 H 2 O+S1 mkasked 2×
- Q6Oxides of aluminium and zinc are:1 mkasked 3×
- Q6Identify a group of the unsaturated hydrocarbons from the following:1 mk
- Q6The process in which transport of soluble products of photosynthesis takes place in plants is known as:1 mkasked 3×
- Q6In human beings, when the process of digestion is completed, the (i) proteins, (ii) carbohydrates, and (iii) fats are…1 mkasked 3×
- Q6Tooth decay begins at the pH of:1 mk
- Q7Identify an involuntary action from the following:1 mk
- Q7Which one of the following reactions is different from the remaining three?1 mkasked 3×
- Q7A plant growth inhibitor hormone which causes wilting of leaves is called:1 mkasked 3×
- Q7Consider the following statements about homologous series of carbon compounds: All succeeding members differ by - CH 2…1 mkasked 3×
- Q7The correct sequence of events when someone's hand touches a hot object unconsciously:1 mkasked 2×
- Q7The structural formula of Cyclohexane is1 mk
- Q7MnO 2+4 HCl → MnCl 2+2 H 2 O+Cl 2 The reaction given above is a redox reaction because in this case:1 mkasked 3×
- Q8Which one of the following statements is NOT true?1 mk
- Q8Sense organ in which olfactory receptors are present is:1 mkasked 3×
- Q8Consider the following statements: (i) The sex of a child is determined by what it inherits from the mother. (ii) The…1 mkasked 2×
- Q8The plants that can be raised by the method of vegetative propagation are:1 mkasked 2×
- Q8Which of the following statement(s) is (are) true about human heart? Right atrium receives oxygenated blood from lungs…1 mkasked 3×
- Q8The part of the flower which attracts insects for pollination is/are:1 mk
- Q8In the given diagram the leaf shown belongs to which plant?1 mk
- Q8Select from the following a plant hormone which promotes cell division.1 mk
- Q9Chromosomes: (i) carry hereditary information from parents to the next generation. (ii) are thread like structures…1 mkasked 3×
- Q9The part of seed which is a source of food during germination of seed is:1 mkasked 3×
- Q9United Nations Environment Programme forged an agreement to1 mk
- Q9Select out of the following a gland which does NOT occur as a pair in the human body:1 mkasked 3×
- Q9Part(s) of a flower which attracts insects for pollination is (are)1 mkasked 2×
- Q9The incorrect statement about placenta is:1 mkasked 3×
- Q10In an experiment to study independent inheritance of two separate traits: shape and colour of seeds, the ratio of the…1 mkasked 2×
- Q10A zygote is formed by the fusion of a male gamete and a female gamete. The number of chromosomes in the zygote of a…1 mkasked 3×
- Q10In a nerve cell, the site where the electrical impulse is converted into a chemical signal is known as:1 mkasked 3×
- Q10In human respiratory system, when a person breathes in, the position of ribs and diaphragm will be:1 mkasked 3×
- Q10Select from the following the conditions responsible for the rapid spread of bread mould on a slice of bread: (i)…1 mkasked 3×
- Q10Select from the following a plant hormone which promotes cell division.1 mk
- Q10Which one of the following statements is TRUE for Hydra, Amoeba and Spirogyra?1 mk
- Q11Offsprings formed as a result of sexual reproduction produce more variations because1 mk
- Q11Which of the following statement (s) is (are) true about human heart? Right atrium receives oxygenated blood from lungs…1 mkasked 3×
- Q11Absolute refractive index of glass and water is 3/2 and 4/3 respectively. If the speed of light in glass is 2 × 10^8 m…1 mkasked 3×
- Q11Identify the mode of asexual reproduction in the following organism:1 mk
- Q11A stomata closes when: (i) it needs carbon dioxide for photosynthesis. (ii) it does not need carbon dioxide for…1 mk
- Q11How will the image formed by a convex lens be affected, if the upper half of the lens is wrapped with a black paper?1 mkasked 3×
- Q11Which one of the following organism is represented by this diagram?1 mk
- Q11A stomata closes when: (i) it needs carbon dioxide for photosynthesis. (ii) it does not need carbon dioxide for…1 mk
- Q12When a beam of white light passes through a region having very fine dust particles, the colour of light mainly…1 mkasked 3×
- Q12At what distance from a convex lens should an object be placed to get an image of the same size as that of the object…1 mkasked 3×
- Q12Which one of the following organ is NOT a part of human female reproductive system?1 mk
- Q12A cross between two tall pea plants resulted in offsprings having a few dwarf plants. The gene-combination of the…1 mkasked 2×
- Q12A cross made between two pea plants produces 50 % tall and 50 % short pea plants. The gene combination of the parental…1 mkasked 3×
- Q12The phenomena of light involved in the formation of rainbow are:1 mkasked 3×
- Q12Sex determination depends upon the environment in1 mk
- Q13The Phenomena of light involved in the formation of a rainbow in the sky are1 mkasked 2×
- Q13The colour of light for which the refractive index of glass is minimum, is:1 mkasked 3×
- Q13Consider the following combinations of resistors: I II III IV The combinations having equivalent resistance 1 Ω is/are:1 mkasked 2×
- Q13Consider the following statements in the context of human eye: The diameter of the eye ball is about 2.3 cm. Iris is a…1 mkasked 2×
- Q13The lens system of human eye forms an image on a light sensitive screen, which is called as:1 mkasked 2×
- Q14The current carrying device which produces a magnetic field similar to that of a bar magnet is:1 mkasked 3×
- Q14The maximum resistance of a network of five identical resistors of 1/5 Ω each can be -1 mkasked 2×
- Q14In case of four wires of same material, the resistance will be minimum if the diameter and length of the wire…1 mkasked 3×
- Q14An electric iron of resistance 20 Ω draws a current of 5 A. The heat developed in the iron in 30 seconds is:1 mkasked 3×
- Q14S.I. unit of electrical resistivity is1 mk
- Q14The pattern of the magnetic field produced inside a current carrying solenoid is:1 mkasked 3×
- Q14In the given circuit the total resistance between X and Y is:1 mk
- Q14In bifocal lenses used for the correction of presbyopia:1 mk
- Q15A rectangular loop ABCD carrying a current I is situated near a straight conductor XY, such that the conductor is…1 mkasked 3×
- Q15The minimum resistance which can be made using five resistors each of resistance 10 Ω is:1 mk
- Q15A uniform magnetic field exists in the plane of paper as shown in the diagram. In this field, an electron (e^-) and a…1 mkasked 3×
- Q15A food chain will be more advantageous in terms of energy if it has1 mkasked 3×
- Q15The speed of light in vacuum is 3 × 10^8 m / s. If the speed of light in a medium is 2.25 × 10^8 m / s, the absolute…1 mk
- Q15Study the I-V graph for three resistors of resistances R 1, R 2 and R 3 and select the correct statement from the…1 mkasked 2×
- Q15Identify the food chain in which the organisms of the second trophic level are missing:1 mkasked 3×
- Q16Consider the following combinations of resistors: The combinations having equivalent resistance 1 Ω is/are:1 mk
- Q16In which of the following organisms, multiple fission is a means of asexual reproduction?1 mkasked 3×
- Q16Consider the following statements about ozone: Ozone is poisonous gas. Ozone shields the earth's surface from the…1 mkasked 3×
- Q16Strength of magnetic field produced by a current carrying solenoid DOES NOT depend upon:1 mkasked 2×
- Q16Study the following statements: A fuse in a circuit prevents damage to the circuit due to overloading. Total resistance…1 mk
- Q16Some wastes are given below: (i) Garden waste (ii) Ball point pen refills (iii) Empty medicine bottles made of glass…1 mkasked 3×
- Q16Which one of the following is not a natural ecosystem?1 mkasked 3×
- Q17Assertion: Carbon reduces the oxides of Sodium and Magnesium. Reason (R): Sodium and Magnesium have more affinity for…1 mk
- Q17to 20 consists of two statements - Assertion and Reason (R), answer these questions selecting the appropriate option…1 mk
- Q17to 20 consists of two statements - Assertion and Reason (R), answer these questions selecting the appropriate option…1 mk
- Q17Assertion: The extraction of metals from their sulphide ores cannot take place without roasting of the ore. Reason (R):…1 mkasked 3×
- Q17Assertion: Some vegetable oils are healthy. Reason (R): Vegetable oils generally have long unsaturated carbon chains.1 mkasked 3×
- Q17Assertion: Different metals have different reactivities with water and dilute acids. Reason (R): Extraction of a metal…1 mk
- Q17Assertion: A piece of Zinc metal gets reddish brown coating when kept in copper sulphate solution for some time. Reason…1 mk
- Q17Assertion: Hydrogen gas is not evolved when zinc reacts with nitric acid. Reason (R): Nitric acid oxidises the hydrogen…1 mkasked 3×
- Q18Assertion: Most of the plants close their stomata at night. Reason (R): Closing of stomata helps to conserve water as…1 mk
- Q18Assertion: Offsprings produced by asexual reproduction are genetically similar to the parents. Reason (R): Asexual…1 mk
- Q18Assertion: Human female has a perfect pair of sex chromosome. Reason (R): Sex chromosome contributed by the human male…1 mkasked 3×
- Q18Assertion: In the human heart ventricles have thicker muscular walls than atria. Reason (R): Ventricles have to pump…1 mkasked 2×
- Q18Assertion: Red light signals are used to stop the vehicles on the road. Reason (R): Red coloured light is scattered the…1 mk
- Q18Assertion: Accumulation of harmful chemicals is maximum in the organisms at the highest trophic level of a food chain.…1 mkasked 3×
- Q18Assertion: A piece of Zinc metal gets reddish brown coating when kept in copper sulphate solution for some time. Reason…1 mk
- Q18Assertion: Sex of the children will be determined by what they inherit from their mother. Reason (R): Women have XX sex…1 mkasked 3×
- Q19Assertion: Electrons move from lower potential to higher potential in a conductor. Reason (R): A dry cell maintains…1 mkasked 3×
- Q19Assertion: In human beings, males have 'XX' sex chromosomes and females have 'XY' sex chromosomes. Reason (R): Sex of…1 mk
- Q19Assertion: Myopic eye cannot see distant objects distinctly. Reason (R): For the correction of myopia converging lenses…1 mkasked 2×
- Q19Assertion: Offsprings produced by asexual reproduction are genetically similar to the parents. Reason (R): Asexual…1 mk
- Q19Assertion: The colour of clear sky appears blue. Reason (R): Light of blue colour has longer wavelength as compared to…1 mk
- Q19Assertion: Red light signals are used to stop the vehicles on the road. Reason (R): Red coloured light is scattered the…1 mk
- Q19Assertion: Magnetic field lines never intersect each other. Reason (R): If they intersect, then at the point of…1 mkasked 3×
- Q19Assertion: The rate of breathing in aquatic organisms is much faster than in terrestrial organisms. Reason (R): The…1 mkasked 3×
- Q20Assertion: Producers are capable of using light energy from the sun to make food available in an ecosystem. Reason (R):…1 mk
- Q20Assertion: Ozone layer protects the surface of the Earth from harmful UV radiations. Reason (R): Chlorofluorocarbons…1 mkasked 2×
- Q20Assertion: Oxygen is essential for all aerobic forms of life. Reason (R): Free oxygen atoms combine with molecular…1 mkasked 3×
- Q20Assertion: The rainbow is a natural spectrum of sunlight in the sky. Reason (R): Rainbow is formed in the sky when the…1 mkasked 3×
- Q20Assertion: Green plants trap only 1\% of the energy of sunlight that falls on their leaves. Reason (R): All green…1 mk
- Q20Assertion: The deflection of a compass needle placed near a current carrying wire decreases when the magnitude of an…1 mkasked 3×
- Q20Assertion: Metals in the middle of activity series are found in nature as sulphides or carbonates. Reason (R): The…1 mk
- Q20Assertion: Receptors are usually located in our sense organs and perceive a particular stimulus. Reason (R): Different…1 mk
- Q20Assertion: The waste we generate daily may be biodegradable or non-biodegradable. Reason (R): The waste generated, if…1 mk
- Q21Copper powder is taken in a china dish and heated over a burner. Name the product formed and state its colour. Write…2 mkasked 3×
- Q21Write the essential conditions for following reaction to take place and name its types: 2 AgCl → 2 Ag+Cl 2 Complete the…2 mk
- Q21Name the type of chemical reaction in which calcium oxide reacts with water. Justify your answer by giving balanced…2 mk
- Q21When a few drops of Barium chloride solution are added to an aqueous solution of Sodium sulphate, a white precipitate…2 mk
- Q21(i) Write the significance of peripheral nervous system in human beings. (ii) How is human brain protected from…2 mk
- Q211 gram of solid sodium chloride was taken in a clean and dry test tube and concentrated sulphuric acid was added to it.…2 mkasked 3×
- Q21Define a decomposition reaction. Write an equation to show thermal decomposition of ferrous sulphate crystals. OR What…2 mk
- Q21"No precipitation reaction can occur without exchange of ions between the two reactants." Justify this statement giving…2 mk
- Q21Give one example of each of the following: (i) Chemical reaction showing evolution of gas. (ii) Change in the colour of…2 mk
- Q21When magnesium ribbon is burnt in air, an ash of white colour is produced. Write chemical equation for the reaction…2 mk
- Q22The melting and boiling points of carbon compounds are generally low and they are largely non-conductors of…2 mk
- Q22State one role of each of the following in human digestive system: (i) Hydrochloric acid (ii) Villi (iii) Anal…2 mk
- Q22Photosynthesis takes place in the leaves and the food prepared by it reaches other parts of the plants. Name the…2 mk
- Q22Name the blood vessel which brings blood to the kidneys. Why is nephron called a basic filtration unit of kidney? Write…2 mk
- Q22When a soap is dissolved in water, the soap molecules form structures. What are these structures called? Draw a…2 mk
- Q22(i) Give reason why herbivorous animals have longer, small intestine than carnivorous animals? (ii) Although 'Pepsin'…2 mk
- Q22List any two pairs of visible contrasting characters of garden pea plants used by Mendel for his experiments stating…2 mk
- Q22A spatula full of sodium carbonate is taken in a test tube and 2 mL of dilute ethanoic acid is added to it. Write a…2 mk
- Q22Identify the functional group present in the following compounds and also name them: H- HH HH-C-OH2 mk
- Q22Distinguish between a saturated and an unsaturated hydrocarbon by flame test. List the products of combustion reaction…2 mk
- Q22Where are auxins synthesized? How do they promote phototropism?2 mkasked 3×
- Q22Write the formula and the molecular mass of the third homologue of alcohols. State how the boiling point of an alcohol…2 mk
- Q22Two test tubes A and B are taken, each containing one mL of starch solution. Add 1 mL of saliva to test tube 'A' only…2 mk
- Q23Draw a labelled diagram to show the pattern of magnetic field lines produced due to a current carrying straight…2 mk
- Q23We need to water the soil in plants on a regular basis. But it ultimately reaches the leaves of the plant. Explain how…2 mkasked 3×
- Q23"Stability of DNA in a species is ensured during sexual reproduction." Justify the statement.2 mk
- Q23Name two types of germ cells present in human beings. List two structural differences between the two.2 mk
- Q23Sometimes while running, the athletes suffer from muscle cramps. Why? How is the respiration in this case different…2 mkasked 3×
- Q23Mendel crossed a round and yellow seeded pea plant with a wrinkled and green seeded pea plant. What did the plants of F…2 mk
- Q23List any two pairs of visible contrasting characters of garden pea plants used by Mendel for his experiments stating…2 mk
- Q23How is the movement of leaves of a sensitive plant different from the downward movement of the roots? OR There is a…2 mk
- Q23A ray of light falls making an angle of incidence θ on the surface of a glass slab. Draw a labelled ray diagram to show…2 mk
- Q23Translate the following statement into a balanced chemical equation. "When barium chloride reacts with aluminium…2 mk
- Q24Some unicellular organisms such as Plasmodium and Leishmania differ in the manner in which they reproduce. Name and…2 mk
- Q24Identify the organ in the human female reproductive system where the sperm encounters the egg cell. What will happen if…2 mk
- Q24In which region of the brain is (i) medulla and (ii) cerebrum located? State one function of each. OR Name a hormone…2 mk
- Q24Mendel crossed pea plants with two pairs of contrasting characters. He observed 4 types of combinations in F 2…2 mk
- Q24Draw a labelled diagram to show the pattern of magnetic field lines produced due to a current carrying straight…2 mk
- Q24When do we say that a particular person is suffering from hypermetropia? List two causes of this defect. Name the type…2 mkasked 3×
- Q24The survival of a species is promoted through creation of variations. Illustrate with an example.2 mk
- Q24Explain how the original number of chromosomes present in the parents are restored in the progeny. Name the cell…2 mk
- Q24An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position of the image…2 mkasked 2×
- Q24Explain how equal genetic contribution of male and female parents is ensured in the progeny.2 mk
- Q24State two laws of refraction of light. OR Define the term absolute refractive index of a medium. A ray of light enters…2 mkasked 2×
- Q25Show how you would connect three resistors each of resistance 6 Ω, so that the combination has a resistance of 9 Ω.…2 mkasked 2×
- Q25Mention the pathway of urine in our body starting from the organ of its formation to its excretion. What will happen if…2 mk
- Q25Draw a labelled diagram to show the pattern of magnetic field lines produced due to a current carrying straight…2 mk
- Q25List any two pairs of visible contrasting characters of garden pea plants used by Mendel for his experiments stating…2 mk
- Q25Draw the pattern of the magnetic field lines due to a straight current carrying conductor indicating the direction of…2 mk
- Q25Define power of a lens. Find power of a lens whose focal length is 50 cm.2 mk
- Q25What would have been the colour of the sky, if the Earth had no atmosphere? Give reason to justify your answer.2 mk
- Q25A person suffering from an eye defect uses lenses of power -1 D. Name the defect of vision and list its two causes.…2 mk
- Q25The heat produced at a point due to concentration of sunlight by a convex lens burns a paper. Explain why it happens.…2 mk
- Q25A person suffering from presbyopia needs bifocal lens. If he needs two lens of power - 4 · 0 dioptre and +2 · 0…2 mk
- Q25Name the phenomenon of light responsible for Tyndall effect. Write an event where this phenomenon can be observed.2 mk
- Q25"The linear magnification produced by a spherical mirror is + 3." Based on this statement answer the following…2 mk
- Q25Use Ohm's law to determine the potential difference across the 3 Ω resistor in the circuit shown in the following…2 mkasked 3×
- Q26The filament of an electric lamp draws a current of 0 · 5 A, which lights for 2 hours. Calculate the charge that flows…2 mk
- Q26Translate the following statements into chemical equations and then balance them: (i) Solution of barium chloride and…2 mk
- Q26An electric source can supply a charge of 500 coulomb. If the current drawn by a device is 25 mA, find the time in…2 mk
- Q26An electric source can supply a charge of 750 coulomb. If the current drawn by a device is 15 mA, find the time in…2 mk
- Q26Two wires A and B of same material, having same lengths and diameters 0.2 mm and 0.3 mm respectively, are connected one…2 mk
- Q26Name the term used for the materials which cannot be broken down by biological processes. Give two ways by which they…2 mkasked 3×
- Q26(i) Two magnetic field lines do not intersect each other. Why? (ii) How is a uniform magnetic field in a given region…2 mkasked 3×
- Q26What are decomposers? List two consequences of their absence in an ecosystem.2 mk
- Q26Define the terms biodegradable and non-biodegradable substance. Classify the following items into these two categories:…2 mk
- Q26State Joule's law of heating. How is this effect useful in electric circuits where fuse is used as a safety device?2 mk
- Q26Give reasons for the following: Food web is more stable than a food chain in an ecosystem. A food chain should not have…2 mk
- Q26Calculate the resistance of a copper wire of length 1000 m and area of cross-section 2 mm^2. Resistivity of copper is 1…2 mk
- Q27Sodium metal is stored under kerosene oil. Why? Some metal oxides are soluble in water. What are the aqueous solutions…3 mk
- Q27Answer the following questions in the context of electrolysis of water: Why is this reaction/process called a…3 mk
- Q27State giving reason the reduction process to obtain the following metals from their compounds: (i) Mercury, (ii) Copper…3 mk
- Q27Give reasons for the following: (i) Alveoli in lungs are richly supplied with blood capillaries. (ii) Respiratory…3 mk
- Q27Write one chemical equation each for the chemical reaction in which the following have taken place: (i) Change in…3 mkasked 2×
- Q27A small amount of copper oxide was taken in a beaker and dilute hydrochloric acid was added with continuous stirring of…3 mk
- Q27It is observed that Calcium on reaction with water floats on its surface. Explain why it happens. Also write a balanced…3 mkasked 2×
- Q27Study the experimental set-up shown in the diagram and write chemical equation for the chemical reaction involved. Name…3 mkasked 2×
- Q27Name the chemical reaction that occurs between iron (III) oxide and aluminium metal. Write its balanced chemical…3 mk
- Q27Write the common name and the chemical name of the compound CaSO 4 · 1/2 H 2 O. Write the method of its preparation.…3 mkasked 2×
- Q27State reasons for the following: Zinc oxide is an amphoteric oxide. Sodium metal is stored in bottle filled with…3 mk
- Q28Write chemical equations for the following reactions, giving the conditions for the reaction in each case: Reaction of…3 mk
- Q28Why is the conversion of ethanol to ethanoic acid an oxidation reaction? Name the oxidising agent used in this…3 mkasked 2×
- Q28Draw a labelled diagram to show electrolytic refining of copper. State what happens when electric current is passed…3 mkasked 2×
- Q28Suggest an activity to differentiate between the chemical properties (acidic or basic character) of the product…3 mk
- Q28State reasons for the following: Zinc oxide is an amphoteric oxide. Calcium starts floating when immersed in water. In…3 mk
- Q28State giving reason the reduction process to obtain the following metals from their compounds: (i) Mercury, (ii) Copper…3 mk
- Q28(i) The pH of a sample of tomato juice is 4.6. How is this juice likely to be in taste? Give reason to justify your…3 mkasked 2×
- Q28Write electronic configuration of Sodium (At. No.11) and Oxygen (At. No. 8) and show the formation of the ionic…3 mk
- Q28Name the ore of mercury and state the form in which it is found in nature. Write the chemical equations along with the…3 mkasked 2×
- Q28In angiosperms why fertilisation cannot take place in flowers if pollination does not take place? Where is zygote…3 mk
- Q29List any two contraceptive methods practised only by women. Mention how these methods work. Write the two roles…3 mk
- Q29(i) Why is respiratory pigment needed in multicellular organisms with large body size? (ii) Give reasons for the…3 mk
- Q29Taking the example of any two animal hormones along with their gland of secretion, explain how these hormones help (i)…3 mkasked 2×
- Q29Give reasons for the following: (i) Alveoli in lungs are richly supplied with blood capillaries. (ii) Respiratory…3 mk
- Q29Explain with the help of a labelled diagram, the process of reproduction in Hydra by budding. Name the cells used for…3 mkasked 3×
- Q29Name a plant growth hormone synthesized at the shoot tip. Explain its effect on the growth of a plant in response to…3 mk
- Q29State any two observations when an electric current is passed through acidulated water, in a container having each…3 mk
- Q29We water the soil but it reaches the topmost leaves of the plants. Explain in brief the process involved.3 mkasked 2×
- Q30Write the name and location of a hormone which helps a person to respond when chased by a dog. Mention the responses in…3 mk
- Q30Explain the events that take place once a sperm reaches the oviduct till it becomes a foetus. Write the role of…3 mk
- Q30List two differences between dominant traits and recessive traits. What percentage of pea plants in the F 2 generation…3 mk
- Q30In the context of the statement "chlorophyll is necessary for photosynthesis" answer the following questions: (i) What…3 mk
- Q30Give reasons for the following: (i) Alveoli in lungs are richly supplied with blood capillaries. (ii) Respiratory…3 mk
- Q30How is the sex of a newborn individual determined in different species of animals? Give three examples to support your…3 mk
- Q30Write the main difference between aerobic and anaerobic respiration. State the pathway which is common for both. Write…3 mk
- Q30A plant with violet flowers (VV) was crossed with a plant with white flowers (vv). What colour of flowers was obtained…3 mk
- Q30Mendel crossed pure tall pea plants (TT) with pure short pea plants (tt) and obtained F 1 progeny. When the plants of F…3 mkasked 2×
- Q30Name any two pairs of contrasting characters other than height used by Mendel in his experiments. On crossing a tall…3 mk
- Q30Define reflex action. With the help of a flow chart show the path of a reflex action such as sneezing.3 mkasked 3×
- Q30List two constituents of Central Nervous System (CNS). How are these components protected from injuries? Write two…3 mkasked 2×
- Q31An object is placed in front of a concave mirror of focal length 12 cm. If distance of the object from the pole of the…3 mk
- Q31(i) Which organisms have a three-chambered heart? Why do they have three-chambered hearts? (ii) List two functions of…3 mk
- Q31Define the term power of accommodation of human eye. Write the name of the part of eye which plays a major role in the…3 mkasked 2×
- Q31Define the term power of accommodation of human eye. What happens to the image distance in the eye when we increase the…3 mkasked 3×
- Q31Name and explain the phenomenon of light due to which the path of a beam of light becomes visible when it enters a…3 mkasked 3×
- Q31Study the diagram given below and answer the questions that follow: (i) Name the defect of vision represented in the…3 mkasked 2×
- Q31Study the diagram given below and answer the questions that follow: (i) Name the defect of vision depicted in this…3 mkasked 3×
- Q32A 2000 W heater has a resistance of about 25 Ω, whereas a 100 W bulb has a resistance of 500 Ω. When 220 V is applied…3 mk
- Q32Name and state the rule to determine the direction of a: (i) magnetic field produced around a current carrying straight…3 mkasked 2×
- Q32A narrow beam, PQ of white light is passing through a glass prism ABC as shown in the diagram. Draw a ray diagram to…3 mk
- Q32Explain in brief the function of an electric fuse in a domestic circuit. An electric heater of current rating 3 kW; 220…3 mkasked 3×
- Q32What happens when a bundle of wires of soft iron is placed inside the coil of a solenoid carrying a steady current?…3 mk
- Q32Draw a schematic diagram of a circuit consisting of a battery of four dry cells of 1.5 V each, a 2 Ω resistor, a 6 Ω…3 mk
- Q32Draw a diagram to show the pattern of magnetic field lines on a horizontal sheet of paper due to a straight conductor…3 mk
- Q32Define the term solenoid. Draw the pattern of magnetic field lines around a current carrying solenoid. State how this…3 mk
- Q32State Fleming's left hand rule. Apply this rule to determine the direction of force experienced by a straight current…3 mk
- Q32A student fixes a sheet of white paper on a drawing board. He places a bar magnet in the centre of it. He sprinkles…3 mkasked 2×
- Q32"Earth wire is a safety measure in domestic electric circuits." Justify this statement explaining its role in case of…3 mk
- Q32A compound which is prepared from gypsum has the property of hardening when water is mixed in right quantity with it:…3 mk
- Q32How is a solenoid prepared? Differentiate between a circular coil and a solenoid. Draw the pattern of the magnetic…3 mk
- Q33Use of pesticides to protect our crops affect organisms at various trophic levels especially human beings. Name the…3 mkasked 3×
- Q33Plants → Deer → Lion In the given food chain, what will be the impact of removing all the organisms of second trophic…3 mkasked 3×
- Q33State Ohm's law. Write formula for the equivalent resistance R p of the parallel combination of three resistors of…3 mk
- Q33Differentiate between food chain and food web. In a food chain consisting of deer, grass and tiger, if the population…3 mkasked 3×
- Q33Study the picture given below showing three food chains, and and answer the following questions: (i) Name the type of…3 mkasked 2×
- Q33Differentiate between biodegradable and non-biodegradable wastes. We generate a lot of non-biodegradable wastes in our…3 mk
- Q33(i) Name two safety measures commonly used in electric circuits and appliances. (ii) The power rating of an electric…3 mk
- Q33List three advantages of parallel circuits in domestic wiring.3 mk
- Q33(i) Define a decomposition reaction. Write chemical equation for the reaction that occurs when lead nitrate is heated…3 mk
- Q34(i) State whether the currents and potential difference in all the bulbs will be same or different when in a circuit…5 mk
- Q34(i) Give reason why carbon can neither form C^4+ cations nor C^4- anions but form covalent compounds. (ii) What is…5 mkasked 3×
- Q34(i) Define a homologous series of carbon compounds. (ii) Why is the melting and boiling points of C 4 H 8 higher than…5 mkasked 2×
- Q34(i) Five solutions A, B, C, D and E when tested with pH paper showed pH as 4, 1, 13, 7 and 10 respectively. Which…5 mkasked 3×
- Q34(i) Define the term functional group. Identify the functional groups present in the following carbon compounds: (I)…5 mk
- Q34What is a chemical reaction? Describe one activity each to show that a chemical change has occurred in which (i) change…5 mkasked 2×
- Q34When lead nitrate is heated strongly in a boiling tube, two gases are liberated and a solid residue is left behind in…5 mk
- Q34A few crystals of ferrous sulphate were taken in a dry boiling tube and heated. Tiny water droplets were observed in…5 mkasked 2×
- Q34Explain chlor-alkali process and write balanced chemical equations for the reactions that occur. Name the gases…5 mk
- Q35(i) Define a reflex arc. Why have reflex arcs evolved in animals? Trace the sequence of events which occur, when you…5 mkasked 3×
- Q35(i) Distinguish between hormonal co-ordination in plants and animals. (ii) Which part of the brain is responsible for -…5 mkasked 3×
- Q35(i) Name three techniques/devices used by human females to avoid pregnancy. Mention the side effects caused by each.…5 mkasked 3×
- Q35Design an experiment to demonstrate that carbon dioxide is essential for photosynthesis. Write the observation and…5 mkasked 2×
- Q35(i) What are spores? On which structures are they formed? How do they overcome unfavourable conditions? Name the…5 mk
- Q35What is puberty? Write any two changes that occur in boys during early teenage years. List two functions performed by…5 mk
- Q35Name any two sexually transmitted diseases. Prenatal sex determination is prohibited by law. Why? Name any three…5 mk
- Q36(i) State laws of reflection of light. (ii) An object of height 5⋅0 cm is placed at 15 cm in front of a concave mirror…5 mk
- Q36(i) Draw a ray diagram to show the path of the refracted ray in each of the following cases: A ray of light incident on…5 mkasked 3×
- Q36(i) Which type of circuits - series or parallel, should be used when you have to operate different electrical gadgets…5 mk
- Q36Upper half of a convex lens is covered with a black paper. Draw a ray diagram to show the formation of image of an…5 mkasked 3×
- Q36Design an experiment to demonstrate that carbon dioxide is essential for photosynthesis. Write the observation and…5 mk
- Q36(i) Define electric power. Express it in terms of potential difference (V) and resistance (R). (ii) An electric oven is…5 mkasked 2×
- Q36(i) The potential difference across the two ends of a circuit component is decreased to one-third of its initial value,…5 mkasked 2×
- Q36The variation of image distance (v) with object distance (u) for a convex lens is given in the following observation…5 mkasked 2×
- Q37The metals produced by various reduction processes are not very pure. They contain impurities, which must be removed to…4 mkasked 3×
- Q37More than three million carbon compounds have been discovered in the field of chemistry. The diversity of these…4 mkasked 3×
- Q37Three metal samples of magnesium, aluminium and iron were taken and rubbed with sand paper. These samples were then put…4 mkasked 3×
- Q37Carbon is a versatile element that forms the basis of all living organisms and many of the things we use. A large…4 mkasked 3×
- Q37Salts play a very important role in our daily life. Sodium chloride which is known as common salt is used almost in…4 mkasked 3×
- Q37Asexual reproduction involves a single parent to produce offsprings without the formation of gametes. It occurs by the…4 mk
- Q38Pollination is an important process in sexual reproduction of plants. It is an essential process that facilitates…4 mkasked 3×
- Q38Mendel worked out the rules of heredity by working on garden pea using a number of visible contrasting characters. He…4 mkasked 3×
- Q38Human digestive system is a tube running from mouth to anus. Its main function is to breakdown complex molecules…4 mkasked 3×
- Q38Kidneys are vital organs for survival. Several factors like infections, injury or restricted blood flow to kidneys…4 mkasked 3×
- Q38Asexual reproduction involves a single parent to produce offsprings without the formation of gametes. It occurs by the…4 mkasked 2×
- Q39A highly polished surface such as a mirror reflects most of the light falling on it. In our daily life we use two types…4 mkasked 3×
- Q39Study the data given below showing the focal length of three concave mirrors A, B and C and the respective distances of…4 mkasked 3×
- Q39Study the following circuit: On the basis of this circuit, answer the following questions: Find the value of total…4 mkasked 3×
- Q39In a domestic circuit five LED bulbs are arranged as shown. The source voltage is 220 V and the power rating of each…4 mkasked 3×
- Q39When electric current flows in a purely resistive circuit electrical energy gets fully converted into heat energy. The…4 mkasked 3×
Other Science years
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