CBSE Class 10 Science 2023
316 questions · 685 marks · every one with the board’s own marking-scheme answer.
Marks by chapter
Counted from the 316 questions listed below, as the 2023 papers print them. CBSE allocates marks per unit, not per chapter — this is what was observed, not an official CBSE weightage. Every year compared →
| Chapter | Marks | Share |
|---|---|---|
| Life Processes42 questions | 71 | 10.4% |
| Light - Reflection and Refraction22 questions | 67 | 9.8% |
| Electricity23 questions | 58 | 8.5% |
| How do Organisms Reproduce?19 questions | 54 | 7.9% |
| Acids, Bases and Salts29 questions | 53 | 7.7% |
| Metals and Non-metals23 questions | 52 | 7.6% |
| Our Environment23 questions | 51 | 7.4% |
| Carbon and its Compounds20 questions | 48 | 7.0% |
| Chemical Reactions and Equations25 questions | 48 | 7.0% |
| The Human Eye and the Colourful World21 questions | 46 | 6.7% |
| Magnetic Effects of Electric Current26 questions | 45 | 6.6% |
| Control and Coordination20 questions | 42 | 6.1% |
| Heredity17 questions | 39 | 5.7% |
316 questions from 2023
- Q1In the experimental setup given below, it is observed that on passing the gas produced in the reaction in the solution…1 mk
- Q1When Sodium bicarbonate reacts with dilute hydrochloric acid, the gas evolved is:1 mk
- Q1Metal oxides generally react with acids, but few oxides of metal also react with bases. Such metallic oxides are: I.…1 mk
- Q1During electrolysis of water, if the volumes of oxygen and hydrogen evolved at the electrodes are V_O and V_H…1 mk
- Q1To balance the following chemical equation the values of x and y should respectively be: 2 NaOH+x Al_2 O_3 →…1 mk
- Q1Select a pair of olfactory indicators from the following:1 mk
- Q1Select the appropriate state symbols of the products given as X and Y in the following chemical equation by choosing…1 mk
- Q1Which of the following is an example of endothermic process?1 mk
- Q2Select the correct option(s) in the following table:1 mk
- Q2The balanced chemical equation showing reaction between quicklime and water is:1 mk
- Q2A solution turns the colour of turmeric to reddish brown. If the same solution is poured on universal indictor, its…1 mk
- Q2When aqueous solutions of potassium iodide and lead nitrate are mixed, an insoluble substance separates out. The…1 mk
- Q2Few drops of aqueous solution of ammonium chloride are put on a universal indicator paper. The paper turns pink. Study…1 mk
- Q2In the given experimental set-up, if the experiment is carried out separately with each of the following solutions the…1 mk
- Q2The emission of brown fumes in the given experimental set-up is due to1 mk
- Q3MnO_2+x HCl → MnCl_2+y H_2 O+z Cl_2 In order to balance the above chemical equation, the values of x, y and z…1 mk
- Q3A metal ribbon'X'burns in oxygen with a dazzling white flame forming a white ash'Y'. The correct description of X, Y…1 mk
- Q3Study the following chemical reaction: 2 Na( s)+2 H_2 O(l) → 2 NaOH(aq)+H_2( g) ↑ The reducing agent in this reaction…1 mk
- Q3Copper is used for making cooking utensils. Which of the following physical properties of copper is NOT responsible for…1 mk
- Q3In order to balance the following chemical equation, the values of the coefficients x and y respectively are: x…1 mk
- Q3Select the appropriate state symbols of the products given as X and Y in the following chemical equation by choosing…1 mk
- Q4When zinc reacts with sodium hydroxide, the product formed is:1 mk
- Q4Which of the following gives the correct increasing order of acidic strength?1 mk
- Q4The table below has information regarding pH and the nature (acidic/basic) of four different solutions. Which one of…1 mk
- Q4Acid present in tomato is:1 mk
- Q4Acid present in tomato is:1 mk
- Q4Fresh milk has a pH of 6. To delay its curdling, a chemical substance is added to it, which is:1 mk
- Q4Two salts 'X' and 'Y' are dissolved in water separately. When phenolphthalein is added to these two solutions, the…1 mk
- Q4There are four solutions A, B, C, and D with pH values as follows: Which solution(s) would liberate hydrogen gas with…1 mk
- Q5In the given diagram of a closed stomata: (1), (2), (3) and (4) respectively are1 mk
- Q5Among the following, the metal with lowest density is:1 mk
- Q5Which of the following statements is true for an amphoteric oxide?1 mk
- Q5Sodium hydroxide is termed an alkali while Ferric hydroxide is not because:1 mk
- Q5A metal 'X' is used in thermite process. When X is burnt in air it gives an amphoteric oxide 'Y'. 'X' and 'Y' are…1 mk
- Q5Given below are two columns, Column I shows enzymes secreted by the glands in the alimentary canal of human beings and…1 mk
- Q6Hydronium ions are formed by the reaction between:1 mk
- Q6The number of electrons in the outermost shell of the atom of a non-metal can be:1 mk
- Q6Select washing soda from the following:1 mk
- Q6Consider the structures of the three cyclic carbon compounds A, B and C given below and select the correct option from…1 mk
- Q6The name of the salt used to remove permanent hardness of water is:1 mk
- Q6Walking in a straight line and riding a bicycle are the activities which are possible due to a part of the brain.…1 mk
- Q6When ethanol reacts with sodium two products are formed. These products are:1 mk
- Q7A student wants to obtain an erect image of an object using a concave mirror of 10 cm focal length. What will be the…1 mk
- Q7To obtain a magnification of + 2 with a concave mirror of radius of curvature 60 cm the object distance must be1 mk
- Q7The total number of electrons shared in the formation of an ethyne molecule is:1 mk
- Q7A positron enters a uniform magnetic field at right angles to it as shown. The direction of force experienced by the…1 mk
- Q7The following diagram shows the electrolytic refining of copper: Which of the following statements is incorrect…1 mk
- Q7The electron dot structure of chlorine molecule is:1 mk
- Q7In torch lights and head lights of vehicles, the bulb is placed1 mk
- Q7The correct representation of covalent bonding in an oxygen molecule is:1 mk
- Q7Consider the structures of the three cyclic carbon compounds A, B and C given below and select the correct option from…1 mk
- Q7Select the correct option from the following: Salt, Parent acid, Parent base, Nature of salt1 mk
- Q8Select endothermic reaction from the following:1 mk
- Q8The process in which loss of water in the form of vapours from the aerial parts of plants takes place is X, which helps…1 mk
- Q8Bronze is an alloy of1 mk
- Q8Sphincter muscles are present at the exit of:1 mk
- Q8Observe the following diagram and identify the process and its significance from the following options:1 mk
- Q8An organism which breaks down the food material outside the body and then absorbs it is1 mk
- Q9In the following diagram, identify the cells through which massive amounts of gaseous exchange takes place for…1 mk
- Q9During adolescence, reproductive phase starts and:1 mk
- Q9As compared to terrestrial organisms, the rate of breathing in aquatic organisms is:1 mk
- Q9Consider the following statements about small intestine and select the one which is NOT correct:1 mk
- Q9Water in the root enters due to:1 mk
- Q9In an experiment with pea plants, a pure tall plant (TT) is crossed with a pure short plant (tt). The ratio of pure…1 mk
- Q9Opening and closing of stomata is due to:1 mk
- Q10Study the given figure of a Food web and identify the primary consumer in the food web:1 mk
- Q10Consider the following two statements: (i) The trait that expresses itself in F_1 generation. (ii) The trait that keeps…1 mk
- Q10The statement that correctly describes the characteristic(s) of a gene is:1 mk
- Q10Which of the following metals do not corrode in moist air?1 mk
- Q10A cross between pea plant with white flowers (vv) and pea plant with violet flowers (VV) resulted in F_2 progeny in…1 mk
- Q10Which pair of sex chromosome will determine a male?1 mk
- Q10During vigorous exercise, the occurrence of cramps in the outer muscles of an athlete is due to the conversion of…1 mk
- Q10Choose the option giving correct matching the items given in Column - I \& II.1 mk
- Q10Which one of the given statements is incorrect:1 mk
- Q11Select from the following the correct statement about tropic movement in plants:1 mk
- Q11One of the events that does not occur during photosynthesis is:1 mk
- Q11Sensory nerve of a reflex arc carries information from the receptor cells to the:1 mk
- Q11Plants which bear unisexual flowers are:1 mk
- Q11Choose the correct order of the stages of binary fission in Leishmania.1 mk
- Q11In plants the role of cytokinin is:1 mk
- Q11The thread like structures that develop on a moist slice of bread in Rhizopus are1 mk
- Q11The part in which gustatory receptors are present in our body is:1 mk
- Q12The bacterial and the viral infections that may be caused due to unsafe sex respectively are:1 mk
- Q12Select the INCORRECT match (between the plant and its vegetative part) from the following:1 mk
- Q12The change in the focal length of an eye lens in human beings is caused by the action of1 mk
- Q12When an 'X' bearing sperm fertilises the egg, the resulting zygote has the following combination of chromosomes:1 mk
- Q12The number of chromosomes in parents and offsprings of a particular species undergoing sexual reproduction remain…1 mk
- Q12Consider the following chemical equation I and II I. Mg+2 HCl → MgCl_2+H_2 II. NaOH+HCl → NaCl+H_2 O The correct…1 mk
- Q13In the following diagram showing dispersion of white light by a glass prism, the colours 'P' and 'Q' respectively are -1 mk
- Q13If four identical resistors, of resistance 8 ohm, are first connected in series so as to give an effective resistance…1 mk
- Q13Two LED bulbs of 12 W and 6 W are connected in series. If the current through 12 W bulb is 0.06 A the current through 6…1 mk
- Q13The expressions that relate (i) Q, I and t and (ii) Q, V and W respectively are (Here the symbols have their usual…1 mk
- Q13The phenomena of light involved in the formation of rainbow are1 mk
- Q13An object is placed in front of a convex mirror at infinity. According to the New Cartesian Sign Convention, the sign…1 mk
- Q14In domestic electric circuits the wiring with 15 A current rating is for the electric devices which have1 mk
- Q14An electric iron of 1500 W, 200 V and a flash light of 500 W, 200 V are used in homes. The rating of fuse to be used…1 mk
- Q14For verifying Ohm's law, we design an electric circuit diagram in which we show the arrangement of different circuit…1 mk
- Q14A constant current flows in a horizontal wire in the plane of the paper from east to west as shown in the figure. The…1 mk
- Q14Consider the following three flowers namely X, Y and Z. Which flower(s) would develop into a fruit?1 mk
- Q14The correct pattern of magnetic field lines of the field produced by a current carrying circular loop is:1 mk
- Q15The magnetic field inside a long straight current carrying solenoid:1 mk
- Q15A positron enters a uniform magnetic field at right angles to it as shown. The direction of force experienced by the…1 mk
- Q15In a resistive circuit if the current is increased to two times, the percentage change in the amount of heat dissipated…1 mk
- Q15An electric kettle consumes 1 kW of electric power when operated at 220 V. The minimum rating of the fuse wire to be…1 mk
- Q15The resistance of a resistor is reduced to half of its initial value. If other parameters of the electrical circuit…1 mk
- Q15In the following diagram, the position of the needle is shown on the scale of a voltmeter. The least count of the…1 mk
- Q15An alpha particle enters a uniform magnetic field as shown. The direction of motion of the alpha particle is:1 mk
- Q16If the current I through a resistor is increased by 100\% (at constant temperature), the increase in power dissipated…1 mk
- Q16For a current in a long straight solenoid, N and S poles are created at the two ends. Among the following statements,…1 mk
- Q16A positron enters a uniform magnetic field at right angles to it as shown. The direction of force experienced by the…1 mk
- Q16An alpha particle enters a uniform magnetic field as shown. The direction of force experienced by the alpha particle is:1 mk
- Q16Two LED bulbs of 10W and 5W are connected in series. If the current flowing through 5 W bulb is 0.005 A, the current…1 mk
- Q16The resultant magnetic field at point 'P' situated midway between two parallel wires (placed horizontally) each…1 mk
- Q16In human eye the part which allows light to enter into the eye is -1 mk
- Q17Assertion: Sodium oxide is an amphoteric oxide. Reason (R): Metal oxides which react with both acids as well as bases…1 mk
- Q17Assertion: Reaction of Quicklime with water is an exothermic reaction. Reason (R): Quicklime reacts vigorously with…1 mk
- Q17Assertion: The colour of aqueous solution of copper sulphate turns colourless when a piece of lead is added to it.…1 mk
- Q17Assertion: In the following reaction ZnO+C → Zn+CO ZnO undergoes reduction. Reason (R): Carbon is a reducing agent that…1 mk
- Q17Assertion: The magnetic field lines around a current carrying straight wire do not intersect each other. Reason (R):…1 mk
- Q17Assertion: Sodium, calcium and magnesium are obtained by the electrolysis of their molten oxides. Reason (R): These…1 mk
- Q17Assertion: It is advised that while diluting an acid one should add water to acid and not acid to water keeping the…1 mk
- Q18Assertion: Human populations show a great deal of variations in traits. Reason (R): All variations in a species have…1 mk
- Q18Assertion: Genes inherited from the parents decide the sex of a child. Reason (R): X chromosome in a male child is…1 mk
- Q18Assertion: The energy which passes to the herbivores does not come back to autotrophs. Reason (R): The flow of energy…1 mk
- Q18Assertion: An ecosystem consists of biotic components and abiotic components. Reason (R): Biotic and abiotic components…1 mk
- Q18Assertion: The anaerobic respiration which takes place in yeast, has one of the end products as an acid. Reason (R):…1 mk
- Q18Assertion: When a bacterium divides into two, and the resultant two bacteria divide again, the four bacteria produced…1 mk
- Q18Assertion: In humans, if gene is responsible for black eyes and gene is responsible for brown eyes, then the colour of…1 mk
- Q19Assertion: Blood clotting prevents excessive loss of blood. Reason (R): Blood clotting is due to blood plasma and white…1 mk
- Q19Assertion: The angle through which a ray of light bends on passing through a prism is called the angle of deviation.…1 mk
- Q19Assertion: The walls of atria are thicker than those of the ventricles. Reason (R): Ventricles have to pump blood into…1 mk
- Q19Assertion: Amoeba takes in food using finger like extensions of the cell surface. Reason (R): In all unicellular…1 mk
- Q19Assertion: The inner walls of the small intestine have finger like projections called villi which are rich in blood.…1 mk
- Q19Assertion: Testes in human males are located outside the abdominal cavity in scrotum. Reason (R): Scrotum provides a…1 mk
- Q19Assertion: A person suffering from myopia cannot see the distant objects clearly. Reason (R): A converging lens is used…1 mk
- Q20Assertion: The strength of the magnetic field produced at the centre of a current carrying circular coil increases on…1 mk
- Q20Assertion: Magnetic field lines do not intersect each other. Reason (R): Magnetic field lines are imaginary lines, the…1 mk
- Q20Assertion: A current carrying straight conductor experiences a force when placed perpendicular to the direction of…1 mk
- Q20Assertion: Left atrium receives oxygenated blood from pulmonary vein. Reason (R): Right atrium transfers deoxygenated…1 mk
- Q20Assertion: Two magnetic field lines around a current carrying straight wire do not intersect each other. Reason (R):…1 mk
- Q20Assertion: Melting point and boiling point of ethanol are lower than that of sodium chloride. Reason (R): The forces of…1 mk
- Q21(i) A compound 'X' which is prepared from gypsum has the property of hardening when mixed with proper quantity of…2 mk
- Q21State whether the given chemical reaction is a redox reaction or not. Justify your answer. MnO_2+4 HCl → MnCl_2+2 H_2…2 mk
- Q21List two reasons to show that the existence of decomposers is essential in an ecosystem.2 mk
- Q21A metal nitrate 'A' on heating gives a metal oxide along with evolution of a brown coloured gas 'B' and a colourless…2 mk
- Q21On heating 'X' at 373 K, it loses water molecules and becomes 'Y'. 'Y' is a substance which doctors use for supporting…2 mk
- Q21Name a plant hormone responsible for bending of a shoot of a plant when it is exposed to unidirectional light. How does…2 mk
- Q21A plant hormone helps in bending of stem towards light. Name the hormone and explain how is the movement achieved.2 mk
- Q21State two reasons why human-made materials like plastics persist for a long time in the environment.2 mk
- Q21(i) State the essential function performed by ozone at the higher levels of the atmosphere. (ii) Why was there a sharp…2 mk
- Q21A student took a small amount of copper oxide in a conical flask and added dilute hydrochloric acid to it with constant…2 mk
- Q21How is the brain and spinal cord protected in human beings? State one main function each of (i) Medulla and (ii)…2 mk
- Q21What is observed when aqueous solutions of potassium iodide and lead nitrate are mixed together? Name the type of…2 mk
- Q22How is an electric impulse created in human nervous system? Identify the parts of a neuron which helps the nerve…2 mk
- Q22Why is it important to prevent oxygenated and deoxygenated blood from mixing in birds and mammals? Which animals can…2 mk
- Q22What will happen if: Xylem tissue in a plant is removed? We are injured and start bleeding?2 mk
- Q22List two differences between the movement of leaves of a sensitive plant and the movement of a shoot towards light. OR…2 mk
- Q22State the role of the following in the process of digestion: Bile juice and bile salts Pancreatic enzymes2 mk
- Q22Write the role of insulin in regulating blood sugar levels in human body. Mention the disease caused due to it. How is…2 mk
- Q22Name the part of brain which is responsible for the following actions: (i) Maintaining posture and balance (ii) Beating…2 mk
- Q22Write the name and function of parts (i) and (ii) in the diagram of a neuron given below.2 mk
- Q23Give the name of the enzyme present in the fluid in our mouth cavity. State the gland which produces it. What would…2 mk
- Q23Write one specific function each of the following organs in relation with excretion in human beings: (i) Renal Artery…2 mk
- Q23What will happen if: Xylem tissue in a plant is removed? We are injured and start bleeding?2 mk
- Q23Name the type of blood (oxygenated / deoxygenated) transported by each of the following mentioning the path (i.e. from…2 mk
- Q23Mendel crossed a pure tall pea plant (TT) with a pure short pea plant (tt) and obtained all tall plants in F_1…2 mk
- Q23Why is it important to prevent oxygenated and deoxygenated blood from mixing in birds and mammals? Which animals can…2 mk
- Q23List the events in proper sequence that take place during the process of photosynthesis. OR Explain in brief two ways…2 mk
- Q24Write the constituents of solder alloy. Which property of solder makes it suitable for welding electrical wires?2 mk
- Q24What is the other name of'tissue fluid'? Write its two functions.2 mk
- Q24A knife which is used to cut a fruit was immediately dipped into water containing drops of blue litmus solution. If the…2 mk
- Q24In the process of digestion of food in human beings, two protein-digesting enzymes are secreted. Name the enzymes along…2 mk
- Q24Three resistors of 6 Ω, 4 Ω and 4 Ω are connected together so that the total resistance is 8 Ω. Draw a diagram to show…2 mk
- Q24Let the resistance of an electrical device remain constant, while the potential difference across its two ends…2 mk
- Q24Write one important function each of the following in the human respiratory system: Rings of Cartilage Alveoli…2 mk
- Q24Two green plants are kept separately in oxygen free containers, one in the dark and other in sunlight. It was observed…2 mk
- Q24Name the part of the human excretory system where nephrons are found. Write the structure and function of nephrons.2 mk
- Q24Give two reasons, why bile juice is considered to be an important secretion of liver in the process of digestion?2 mk
- Q24When and where does a rainbow appear in the sky? Draw a labelled ray diagram to show its formation. OR What is…2 mk
- Q25A narrow beam XY of white light is passing through a glass prism ABC as shown in the diagram: Trace it on your answer…2 mk
- Q25Observe the following diagram showing an image formation in an eye: Identify the defect of vision shown in the figure.…2 mk
- Q25Observe the following diagram and answer the questions following it: (i) Identify the defect of vision shown. (ii) List…2 mk
- Q25"Although gardens are created by man but they are considered to be an ecosystem. "Justify this statement.2 mk
- Q25Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?2 mk
- Q25Name the hormone secreted in scary situations by animals. Write any three responses which enable the animal body to…2 mk
- Q25A light ray enters from medium A to medium B as shown in the figure. Which one of the two media is denser w.r.t. other…2 mk
- Q25Consider a circular loop of thick copper wire lying horizontally on a table. Let the current pass through the loop…2 mk
- Q25What is the difference between biodegradable and non-biodegradable substances? List two methods of safe disposal of…2 mk
- Q25V - I graph for two conducting wires A and B are as shown. If both wires are of the same length and same diameter,…2 mk
- Q25Write the sequence of events that involve response of a person when a dust particle is inhaled through the nose by him.2 mk
- Q26We do not clean ponds or lakes but an aquarium needs to be cleaned regularly. Why?2 mk
- Q26Use of several pesticides which results in excessive accumulation of pesticides in rivers or ponds, is a matter of deep…2 mk
- Q26On heating 'X' at 373 K, it loses water molecules and becomes 'Y'. 'Y' is a substance which doctors use for supporting…2 mk
- Q26Draw magnetic field lines produced around a straight current carrying conductor passing through a cardboard. How will…2 mk
- Q26"Ozone, although a deadly poison, performs an essential function for the earth and its inhabitants." Explain.2 mk
- Q26State the rule to determine the direction of a magnetic field produced around a straight conductor carrying current and…2 mk
- Q26How do harmful chemicals get accumulated progressively at each trophic level in a food chain?2 mk
- Q26In the following food chain, if 50 J of energy was available to the hawk, how much energy would have been present at…2 mk
- Q26What is meant by trophic level? On an average, what percentage of energy is transferred to the second trophic level…2 mk
- Q27Define a double displacement reaction. Write the chemical equation of a double displacement reaction which is also a…3 mk
- Q27(i) While electrolysing water before passing the current some drops of an acid are added. Why? Name the gases liberated…3 mk
- Q27Write a balanced equation to show the reaction that occurs when a piece of aluminium is dipped in a dilute solution of…3 mk
- Q27Identify the reducing agent in the following reactions: (i) 4 NH_3+5 O_2 → 4 NO+6 H_2 O (ii) H_2 O+F_2 → HF+HOF (iii)…3 mk
- Q27Define oxidation. Identify the oxidising agent in the following reactions and balance the chemical equations: (i) Pb_3…3 mk
- Q27Explain how some harmful chemicals enter our bodies through the food chain. Why is the concentration of these harmful…3 mk
- Q27Write down the balanced chemical equations for the following reactions and identify the type of reaction in each case.…3 mk
- Q27Silver chloride kept in a china dish turns grey in sunlight. Write the colour of silver chloride when it was kept in…3 mk
- Q27A chemical compound X is used in glass, soap and paper industries. On treatment with ethanoic acid, it forms salt,…3 mk
- Q27Explain the process of transport of oxygenated and deoxygenated blood in a human body.3 mk
- Q27Consider the following salts: (i) YCl (ii) NH_4 X (iii) ZCO_3 What would be the pH of the salt solution if in YCl, Y is…3 mk
- Q28With the help of suitable chemical equations, list the two main differences between roasting and calcination. How is…3 mk
- Q28Copper reacts with a moist gas 'A' in the air and slowly loses its shiny brown surface. It turns green. Identify 'A'…3 mk
- Q28Sometimes the pH of our mouth gets lower than 5 · 5. Why? A basic salt 'X' is obtained by heating baking soda followed…3 mk
- Q28(i) What property do acids and bases have in common? Explain it with an example. (ii) A compound which is prepared from…3 mk
- Q28Suggest one remedial measure each to counteract the change in pH in human beings in following cases: (i) Production of…3 mk
- Q28A substance 'X' is used as a building material and is insoluble in water. When it reacts with dil. HCl, it produces a…3 mk
- Q28(i) Suggest a safe procedure of diluting a strong concentrated acid. (ii) Name the salt formed when sulphuric acid is…3 mk
- Q29(i) State the role of ATP in cellular respiration. (ii) What ensures sufficient exchange of gases in plants? (iii)…3 mk
- Q29A student wants to project the image of a candle flame on a screen 60 cm in front of a mirror by keeping the candle at…3 mk
- Q29With the help of an activity, explain the action of saliva on the food we eat. Why is bile juice important in the…3 mk
- Q29A person is suffering from an eye defect in which the far point of the eye is nearer than infinity. Identify the…3 mk
- Q29Some plants like pea plants have tendrils which help them to climb up other plants. Explain how is it done. Name the…3 mk
- Q29The magnification produced when an object is placed at a distance of 20 cm from a spherical mirror is+1/2. Where should…3 mk
- Q29A student has focussed the image of an object of height 3 cm on a white screen using a concave mirror of focal length…3 mk
- Q29(i) How does Paramecium obtain its food? (ii) List the role of each of the following in our digestive system:…3 mk
- Q29(i) What is meant by excretion? (ii) Name the organ that connects the kidneys with the urinary bladder. State its…3 mk
- Q29Name the gland and the hormone secreted by it in scary situations in human beings. List any two responses shown by our…3 mk
- Q29(i) What is the first step in the breakdown of glucose during aerobic and anaerobic respiration? Where does it take…3 mk
- Q29List two differences in the characteristic properties of the virtual images formed by the two types of spherical lenses…3 mk
- Q29Write the percentage of (i) solar energy captured by the autotrophs and (ii) energy transferred from autotrophs to the…3 mk
- Q29Draw a labelled diagram of a common type of bifocal lens. State the function of each of its parts. Name the defect for…3 mk
- Q30An object is kept at a distance of 1m from a lens of power+2D: (i) Identify the type of lens. (ii) Calculate its focal…3 mk
- Q30Complete the following ray diagram to show the formation of image: Mention the nature, position and size of the image…3 mk
- Q30Define the following terms in the context of a diverging mirror: (i) Principal focus (ii) Focal length Draw a labelled…3 mk
- Q30With the help of an appropriate example, justify that some of the chemical reactions are determined by Change in…3 mk
- Q30Explain the directional movement due to growth in response to touch in a pea plant.3 mk
- Q30(i) An object of 5 cm height is placed at a distance of 20 cm from the optical centre of a concave lens of focal length…3 mk
- Q30The image of an object formed by a lens is of same size but inverted. If the object distance is 30 cm, calculate (i)…3 mk
- Q30Name the hormone released and the gland which secretes it in human beings during scary situations. How does the body…3 mk
- Q31A person is unable to see clearly a poster fixed on a distant wall. He however sees it clearly when standing at a…3 mk
- Q31State reasons for Myopia. With the help of ray diagrams, show the image formation by a myopic eye, and correction of…3 mk
- Q31(i) State the rule used to find the force acting on a current carrying conductor placed in a magnetic field. (ii) Given…3 mk
- Q31The power of a lens is+4D. Find the focal length of this lens. An object is placed at a distance of 50 cm from the…3 mk
- Q31A reddish brown metal used in electrical wires when powdered and heated strongly turns black. When hydrogen gas is…3 mk
- Q31(i) How does Paramecium obtain its food? (ii) List the role of each of the following in our digestive system:…3 mk
- Q31A student has focussed the image of an object of height 3 cm on a white screen using a concave mirror of focal length…3 mk
- Q31State one important function of the following parts of the human eye: (i) Retina (ii) Pupil State the role of ciliary…3 mk
- Q31Give reasons for the following: Danger signals installed at airports and at the top of tall buildings are of red…3 mk
- Q32(i) State the rule used to find the force acting on a current carrying conductor placed in a magnetic field. (ii) Given…3 mk
- Q32(i) A straight cylindrical conductor is suspended with its axis perpendicular to the magnetic field of a horse-shoe…3 mk
- Q32What is a solenoid? When does a solenoid behave as a magnet? Draw the pattern of the magnetic field produced inside it…3 mk
- Q32(i) Why is acidified water considered to be a good conductor of electricity? (ii) Write a chemical equation showing the…3 mk
- Q32What is a solenoid? Draw a diagram to show the pattern of magnetic field around a current carrying solenoid. Name the…3 mk
- Q32List two factors on which the magnitude of magnetic field produced by a current carrying straight conductor depends.…3 mk
- Q32Write the chemical composition of tooth enamel. Under what conditions of pH it starts corroding? Explain the reason of…3 mk
- Q32Explain the meaning of overloading of an electrical circuit. List two possible causes due to which overloading may…3 mk
- Q32(i) Why is an alternating current (A. C. ) considered to be advantageous over direct current (D. C. ) for the long…3 mk
- Q32How is a universal indicator better than litmus solution? State two features of pH scale. Why should we not add water…3 mk
- Q33Draw a labelled diagram to show (i) dispersion of a beam of white light, and (ii) formation of a rainbow.3 mk
- Q33If a harmful chemical enters in a food chain comprising peacock, plants, rats and snakes, which of these organisms is…3 mk
- Q33(i) Why does a kitchen garden called an artificial ecosystem while a forest is considered to be a natural ecosystem?…3 mk
- Q33Write the percentage of (i) solar energy captured by the autotrophs and (ii) energy transferred from autotrophs to the…3 mk
- Q33State the change in colour observed in each of the following cases mentioning the reason: Silver chloride is exposed to…3 mk
- Q33Write one difference between biodegradable and non-biodegradable wastes. List two impacts of each type of the…3 mk
- Q33A person cannot see distinctly the object placed beyond 5 m from his eyes. Name the defect of vision the person is…3 mk
- Q33How is ozone formed in the higher levels of the atmosphere? "Damage to the ozone layer is a cause of concern." Justify…3 mk
- Q33Define the term dispersion of white light. State the colour which bends (i) the most, (ii) the least while passing…3 mk
- Q33Explain how some harmful chemicals enter our bodies through the food chain. Why is the concentration of these harmful…3 mk
- Q34(i) A compound 'A' with a molecular formula of C_2 H_4 O_2 reacts with a base to give salt and water. Identify 'A',…5 mk
- Q34A neutral organic compound 'X' (Molecular formula C_2 H_6 O ) on reacting with acidified K_2 Cr_2 O_7 gives an organic…5 mk
- Q34(i) What are isomers? Write the structures of two compounds having molecular formula C_3 H_6 O and give their names.…5 mk
- Q34An acid 'X' and an alcohol 'Y' react with each other in the presence of an acid catalyst to form a sweet smelling…5 mk
- Q34A saturated organic compound 'A' belongs to the homologous series of alcohols. On heating 'A' with concentrated…5 mk
- Q34There are three resistors of 10 Ω, 20 Ω and 30 Ω joined in parallel in a circuit. The potential difference across the…5 mk
- Q34(i) Draw the structure of the following compounds: (ii) How are structure (i) and structure (ii) given below related to…5 mk
- Q34Mention the role of the following organs of human male reproductive system: (i) Testis (ii) Scrotum (iii) Vas-deferens…5 mk
- Q35(i) What is meant by resistance of a conductor? Define its SI unit. (ii) List two factors on which the resistance of a…5 mk
- Q35(i) Where are testes located in the human males and why? State two function of the testes. (ii) In the human female,…5 mk
- Q35Name the two types of pollination and differentiate between them. Explain the post fertilization changes that occur in…5 mk
- Q35Define electric power and state its SI unit. The commercial unit of electrical energy is known as 'unit'. Write the…5 mk
- Q35Give reason for the following: During reproduction inheritance of different proteins will lead to altered body designs.…5 mk
- Q35(i) List three points of difference between nervous and hormonal mechanisms for control and coordination in animals.…5 mk
- Q35(i) Name and explain the two modes of asexual reproduction observed in hydra. (ii) What is vegetative propagation? List…5 mk
- Q35What happens when the egg is not fertilised? How is sperm genetically different from a human egg / ova? List any three…5 mk
- Q35Name the parts of a bisexual flower that are not directly involved in reproduction. Differentiate between self…5 mk
- Q36(i) It is observed that covalent compounds are bad conductors of electricity. Give reason. (ii) Carbon can neither form…5 mk
- Q36(i) Butane had both Carbon - Carbon bonds as well as Carbon - Hydrogen bonds. Draw its structural formula and state the…5 mk
- Q36Explain why carbon forms compounds mainly by covalent bonds. Explain in brief two main reasons for carbon forming a…5 mk
- Q36Give reason for the following: During reproduction inheritance of different proteins will lead to altered body designs.…5 mk
- Q36Draw a ray diagram for showing the convergence of a parallel beam of light by a concave mirror and mark the positions…5 mk
- Q36An object is placed in front of a convex lens of focal length f. If the distance of the object from the lens is 2f,…5 mk
- Q36(i) How is electric current related to the potential difference across the terminals of a conductor? Draw a labelled…5 mk
- Q36Write the chemical equation for the following: (i) Combustion of methane (ii) Oxidation of ethanol (iii) Hydrogenation…5 mk
- Q36Name the type of mirror that should be used to obtain the following types of images: (i) A magnified and virtual image…5 mk
- Q36An electric iron consumes energy at a rate of 880 W when heating is at the maximum rate and 330 W when the heating is…5 mk
- Q36(i) What is meant by resistance of a conductor? Define its SI unit. (ii) List two factors on which the resistance of a…5 mk
- Q36State Ohm's Law. Name and define the physical quantity determined by the slope of V - I curve given in the diagram. Use…5 mk
- Q37The melting points and boiling points of some ionic compounds are given below: These compounds are termed ionic because…4 mk
- Q37The teacher while conducting practicals in the laboratory divided the students into three groups and gave them various…4 mk
- Q37In order to trace the inheritance of traits Mendel crossed pea plants having one contrasting character or a pair of…4 mk
- Q37Almost all metals combine with oxygen to form metal oxides. Metal oxides are generally basic in nature. But some metal…4 mk
- Q37Metals are required for a variety of purposes. For this we need their extraction from their ores. Ores mined from the…4 mk
- Q37On the basis of reactivity metals are grouped into three categories - (i) Metals of low reactivity (ii) Metals of…4 mk
- Q38The most obvious outcome of the reproductive process is the generation of individuals of similar design, but in sexual…4 mk
- Q38All human chromosomes are not paired. Most human chromosomes have a maternal and a paternal copy, and we have 22 such…4 mk
- Q38In order to trace the inheritance of traits Mendel crossed pea plants having one contrasting character or a pair of…4 mk
- Q38The most obvious outcome of the reproductive process is the generation of individuals of similar design, but in sexual…4 mk
- Q38In order to trace the inheritance of traits Mendel crossed pea plants having one contrasting character or a pair of…4 mk
- Q38All the reproductive methods of living organisms are broadly categorized into two types: 1. Asexual reproduction, and…4 mk
- Q38In some families, either rural or urban, females are tortured for giving birth to a female child. They do not seem to…4 mk
- Q39Almost all metals combine with oxygen to form metal oxides. Metal oxides are generally basic in nature. But some metal…4 mk
- Q39Consider the following electrical circuit diagram in which nine identical resistors of 3 Ω each are connected as shown.…4 mk
- Q39The ability of a medium to refract light is expressed in terms of its optical density. Optical density has a definite…4 mk
- Q39Many optical instruments consist of a number of lenses. They are combined to increase the magnification and sharpness…4 mk
- Q39A student took three concave mirrors of different focal lengths and performed the experiment to see the image formation…4 mk
- Q39Hold a concave mirror in your hand and direct its reflecting surface towards the sun. Direct the light reflected by the…4 mk
Other Science years
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