Science 2026 board paper

2026MCQ·1 mark·Q17Combination and decomposition reactions

The volume ratio of hydrogen and oxygen gases liberated during electrolysis of water is

1. (a) 1 : 1
2. (b) 2 : 1
3. (c) 4 : 1
4. (d) 1 : 2

2026MCQ·1 mark·Q18Combination and decomposition reactions

C_6H_{12}O_6(aq) + 6O_2(g) -> 6CO_2(g) + 6H_2O(l). The above reaction is an example of -

1. (a) Displacement Reaction
2. (b) Endothermic Reaction
3. (c) Exothermic Reaction
4. (d) Neutralisation Reaction

2026Short answer·3 marks·Q26Combination and decomposition reactions

Account for the following: (a) White silver chloride turns grey when exposed to sunlight. (b) Lead (II) nitrate on heating releases brown fumes. (c) Bags of oil and fat containing food items are flushed with nitrogen gas.

2026MCQ·1 mark·Q19Acids, bases and indicators

An aqueous solution turns red litmus blue. Excess addition of which of the following solution would reverse the change?

1. (a) Sodium hydroxide
2. (b) Hydrochloric acid
3. (c) Baking soda
4. (d) Slaked lime

2026MCQ·1 mark·Q23How acids and bases react with metals

How will you protect yourself from the heat generated while diluting a concentrated acid?

1. (a) By adding acid to water with constant stirring.
2. (b) By adding water to acid with constant stirring.
3. (c) By adding water to acid followed by base.
4. (d) By adding base to acid with constant stirring.

2026Case based·1 mark·Q28(a)The pH scale and why it matters in everyday life

pH plays an important role in daily life; strength of acids and bases depends on the number of H^+ and OH^- ions produced; the pH scale predicts strength via hydrogen ion concentration. What type of indicator is used to predict how strong an acid or base is?

2026Case based·1 mark·Q28(b)The pH scale and why it matters in everyday life

pH scale predicts strength of acids and bases via hydrogen ion concentration. Three solutions A, B and C showed pH as 3, 5 and 7. Which solution has the highest concentration of H^+ ions?

2026Case based·2 marks·Q28(c)The pH scale and why it matters in everyday life

Strength of acids and bases depends on H^+ and OH^- ions produced. What are strong acids and weak acids?

2026Case based·2 marks·Q28(c-OR)The pH scale and why it matters in everyday life

pH plays an important role in daily life. OR alternative for (c): (i) Under what condition is rainwater called acid rain? (ii) In the following acids, identify weak acids: Nitric acid, hydrochloric acid, acetic acid, sulphuric acid, formic acid.

2026Very short answer·2 marks·Q25Common salt and the chemicals made from it

(a) A compound 'A' is used in soda-lime fire-extinguisher and decomposes on heating to form compound 'B'. Compound 'B' is used for removing permanent hardness of water. Identify 'A' and 'B'. (b) Write chemical formula of Plaster of Paris. At what temperature gypsum is heated to obtain Plaster of Paris?

2026MCQ·1 mark·Q22Physical properties of metals and non-metals

Alloys are homogeneous mixture of metal with a metal or non-metal. Which among the following alloys contain non-metal as one of its constituents?

1. (a) Brass
2. (b) Bronze
3. (c) Amalgam
4. (d) Steel

2026MCQ·1 mark·Q21The reactivity series

Which one of the following metals does not react with cold water?

1. (a) Sodium
2. (b) Potassium
3. (c) Calcium
4. (d) Magnesium

2026Short answer·3 marks·Q27(A)Occurrence and extraction of metals

(i) Which method will be used to convert each of them to their respective metal oxides? (a) Carbonate ore (b) Sulphide ore. (ii) Write a chemical reaction to illustrate the use of aluminium for joining cracked railway tracks. (iii) During extraction of metals, electrolytic refining is used to obtain pure metals. Which material will be used as anode and cathode for the refining of copper metal by this process?

2026Short answer·3 marks·Q27(B)Occurrence and extraction of metals

(i) Write all the reactions involved in the extraction of Zn from ZnS. (ii) Hydrogen gas is not evolved when most of the metals react with nitric acid. Give reason.

2026Long answer·5 marks·Q29(A)Homologous series

(i) Carbon cannot form C^4+ cation and C^4- anion. Explain. (ii) Define homologous series of carbon compounds. Why are the melting and boiling points of C_4H_{10} higher than C_3H_8 or C_2H_6? (iii) What happens when ethanol is heated with acidified potassium dichromate?

2026Long answer·5 marks·Q29(B)Naming carbon compounds

(i) How would you name the following: I. CH_3-CH_2-C(=O)H (i.e. CH_3-CH_2-CHO); II. CH_3-C≡CH. (ii) When ethanol reacts with ethanoic acid in the presence of conc. H_2SO_4, a substance with sweet smell is produced. Answer the following: I. State the class of compounds to which the sweet smelling compounds belong. II. Write the chemical equation for the reaction. (iii) Why soaps do not produce foam with hard water?

2026Assertion-Reason·1 mark·Q24Ethanol and ethanoic acid

Assertion (A): Pure ethanoic acid is also known as glacial acetic acid. Reason (R): Pure ethanoic acid often freezes during winter due to its low melting point of 290 K.

1. (a) Both Assertion
2. (b) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
3. (c) Both Assertion
4. (d) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
5. (e) Assertion
6. (f) is true, but Reason (R) is false.
7. (g) Assertion
8. (h) is false, but Reason (R) is true.

2026MCQ·1 mark·Q20Soaps and detergents

While washing dirty clothes by soap, micelles are formed. Select the correct statement about micelles.

1. (a) The hydrophobic tail of the soap molecule is in the interior of the cluster, whereas hydrophilic end is on the surface of the cluster.
2. (b) The hydrophobic tail is on the surface of the cluster, whereas hydrophilic end is in the interior of cluster.
3. (c) Both hydrophobic tail and hydrophilic end are in the interior of the cluster.
4. (d) Both hydrophobic tail and hydrophilic end are on the surface of the cluster.

2026Long answer·5 marks·Q16(A)Autotrophic nutrition and photosynthesis

(a) Draw a labelled diagram showing open and closed stomatal pore. (b) List the main events that occur during the process of photo-synthesis. (c) Write a balanced chemical equation showing photo-synthesis in plants.

2026MCQ·1 mark·Q1Nutrition in human beings

Observe the given figure and select the statement that correctly states how these fungi obtain nutrition.

1. (a) By eating the bread on which it is growing.
2. (b) By using nutrients from the bread to prepare their own food.
3. (c) By breaking down the nutrients of bread outside the body and then absorbing them.
4. (d) By allowing other organisms to grow on the bread and then consuming them.

2026MCQ·1 mark·Q7Transportation in human beings

In human beings the oxygen rich blood is pumped out to the body by:

1. (a) contraction of right atrium
2. (b) relaxation of left ventricle
3. (c) contraction of right ventricle
4. (d) contraction of left ventricle

2026Very short answer·2 marks·Q10Transportation in plants

"Transpiration in plants is a necessary evil." Comment on the statement giving two reasons.

2026Long answer·5 marks·Q16(B)Excretion in humans and plants

(a) Draw a well-labelled diagram of nephron and label atleast 4 of its parts. (b) Write the role of capillary cluster inside Bowman's capsule. (c) What is meant by selective reabsorption?

2026Very short answer·2 marks·Q12(b)Reflex action and the reflex arc

Sunil unconsciously touched the hot iron rod and immediately withdrew his hand. Which type of action is involved? Also define this action. Draw a flow chart to show the path followed for this action.

2026MCQ·1 mark·Q5The human brain

Following are the statements about the different parts of the brain. Select the correct statements. (i) The thinking part of the brain is the forebrain. (ii) Centres for smell, hearing, memory, sight are located in forebrain. (iii) Salivation, vomiting, blood pressure are controlled by medulla in the hind brain. (iv) Cerebellum does not control the posture and balance of the body.

1. (a) (i), (ii) and (iii)
2. (b) (ii), (iii) and (iv)
3. (c) (i), (ii) and (iv)
4. (d) (i), (iii) and (iv)

2026Case based·1 mark·Q15(a)Coordination in plants: tropisms and plant hormones

Plants exhibit movements in response to environmental stimuli (light, gravity, water, chemicals) regulated by plant hormones; roots and shoots show contrasting responses to the same stimulus. Why is hydrotropism essential for plants?

2026Case based·1 mark·Q15(b)Coordination in plants: tropisms and plant hormones

Plants show movements in response to environmental stimuli regulated by plant hormones. What role does auxin play in the growth of plants?

2026Case based·2 marks·Q15(c)Coordination in plants: tropisms and plant hormones

Plants show movements in response to environmental stimuli regulated by plant hormones. Differentiate between movement shown by the sensitive plant and tropic movement by plants (Two points).

2026Case based·2 marks·Q15(c-OR)Coordination in plants: tropisms and plant hormones

Plants show movements in response to environmental stimuli regulated by plant hormones. OR alternative for (c): How does movement of roots differ from that of shoots in response to gravity and light?

2026Very short answer·2 marks·Q12(a)Hormones in animals

Varun is diabetic. His latest ultrasound reports showed a blockage in his pancreatic duct. How will this affect the dual functioning of the pancreas?

2026Short answer·3 marks·Q13Fission and fragmentation

Give reasons for the following: (a) Adrenal gland is known as the stress gland of the body. (b) Prenatal sex determination is banned in India. (c) Vegetative propagation is advantageous in some plants.

2026Assertion-Reason·1 mark·Q8Fission and fragmentation

Assertion (A): Variations are not often seen in off-springs produced by asexual reproduction. Reason (R): DNA molecule generated by replication is not similar to the original DNA.

1. (a) Both Assertion
2. (b) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
3. (c) Both Assertion
4. (d) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
5. (e) Assertion
6. (f) is true, but Reason (R) is false.
7. (g) Assertion
8. (h) is false, but Reason (R) is true.

2026MCQ·1 mark·Q2Sexual reproduction in flowering plants

If the part 'P' of the flower is removed, which of the following processes will not take place?

1. (a) Formation of pollens
2. (b) Formation of flower
3. (c) Formation of fruit
4. (d) Formation of seed

2026MCQ·1 mark·Q6Inherited traits

Two pea plants, one with round green seeds (RRyy) and another with wrinkled yellow (rrYY) seeds were crossed with each other which produced F_1 progeny that have only round yellow (RrYy) seeds. When F_1 plants are self-pollinated, the F_2 progeny will have which new combination of characters, as compared to the parents: (i) Round, yellow (ii) Round, green (iii) Wrinkled, yellow (iv) Wrinkled, green. Correct options are:

1. (a) (i) and (ii)
2. (b) (i) and (iv)
3. (c) (ii) and (iv)
4. (d) (i) and (iii)

2026Short answer·3 marks·Q14Mendel's monohybrid cross

Study the given table and answer the following questions: [Parents: A pea plant with red flowers was crossed with a pea plant with white flowers. | F_1: 30 seeds were sown and all bore plants with red flowers. | F_2: 44 seeds were sown, 33 plants bore red flowers and 11 plants bore white flowers.] (a) Depict the information given in the table in the form of a cross. (b) Deduce the F_2 phenotypic ratio / F_2 ratio showing external look as well as genotypic/genetic makeup, ratio.

2026Case based·1 mark·Q38(a)Reflection of light by spherical mirrors

A ray diagram shows image formation by a reflecting telescope, which uses large precisely-shaped curved mirrors (and a plane mirror) to gather and focus incoming light to a focal point where the image is formed for observation at the eye-piece. What kind of image of a star is seen by the observer in the eye-piece?

2026Case based·1 mark·Q38(b)Reflection of light by spherical mirrors

A ray diagram shows image formation by a reflecting telescope that uses large curved mirrors to gather and focus light. What kind of mirror is used in this reflecting telescope?

2026Case based·2 marks·Q38(c-OR)Reflection of light by spherical mirrors

A reflecting telescope uses curved mirrors and a plane mirror to form an image. OR alternative for (c): What is the role of plane mirror in image formation by this telescope?

2026Short answer·3 marks·Q35Refraction of light, its laws and refractive index

(a) Observe the given ray diagram and compare: (i) the speed of light in medium A and the speed of light in medium B. (ii) the optical densities of medium B and medium C. (b) Draw a ray diagram for refraction where the optical density of medium 'A' becomes equal to the optical density of medium 'C' and optical density of medium 'B' is greater than the optical density of medium 'A' and medium 'C'.

2026Case based·2 marks·Q38(c)Refraction by spherical lenses and image formation

A reflecting telescope uses curved mirrors and a plane mirror to form an image at the eye-piece. Explain with the reason, what kind of optical device (type of lens or mirror) is used at the eye-piece.

2026MCQ·1 mark·Q30The human eye and power of accommodation

The pair of eye parts responsible for admitting different amount of light in to the eyes is

1. (a) Iris and pupil
2. (b) Ciliary muscles and pupil
3. (c) Retina and Iris
4. (d) Ciliary muscles and cornea

2026MCQ·1 mark·Q31Defects of vision and their correction

The vision defect which arises due to gradual weakening of the ciliary muscles and diminishing flexibility of eye lens is:

1. (a) Myopia
2. (b) Hypermetropia
3. (c) Presbyopia
4. (d) Myopia and hypermetropia both

2026Short answer·3 marks·Q36Dispersion of white light and the rainbow

Explain the phenomenon of rainbow formation in the sky. Draw the labelled ray diagram in support of your explanation.

2026Very short answer·2 marks·Q34Electric current and the electric circuit

(a) Define volt, the unit of potential difference. (b) Calculate the work done required to move an electron between two points A and B located at a potential difference of 100 V in an electric field.

2026Long answer·5 marks·Q39(A)Electric current and the electric circuit

(i) The given electric circuit is a part of an electrical device. Use the information given in the electric circuit diagram to calculate: (I) Potential difference across the ends of resistor R_2. (II) Value of resistor R_2. (III) Value of resistor R_1. [Circuit data: 12 V source with key K; branch with R_1; a 4.0 Ohm resistor carrying 1.5 A; resistor R_2 in parallel; a 2.0 Ohm resistor; total line current 2.0 A.] (ii) Write the factors on which resistance of a conductor depends and derive the formula for resistance of a given conductor.

2026Very short answer·2 marks·Q33(A)Heating effect of electric current

A fuse in electric circuit is rated 4 A. Can it be used with an electric heater of rating 2 kW, 200 V? Explain your answer.

2026Long answer·5 marks·Q39(B)Heating effect of electric current

(i) How much electric current will an electric iron draw from 220 V source if the resistance of its heating element when hot, is 55 Ohm? Calculate the power consumed by the electric iron when it is operated at 220 V. (ii) In a house, 3 bulbs of 100 watt each, are lit for 5 hours daily and an electric heater of 1.0 kW is used for half an hour daily. Calculate the total energy consumed in a month of 30 days and its cost at the rate of Rs. 3.60 per kWh. (iii) With reason explain, why are alloys commonly used to make elements of electrical heating devices.

2026Assertion-Reason·1 mark·Q32Magnetic field and field lines

Assertion (A): With the help of compass, magnetic field lines can be traced outside the bar magnet. Reason (R): The north pole of a compass needle always points towards the south pole of the magnet when brought close to it.

1. (a) Both Assertion
2. (b) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
3. (c) Both Assertion
4. (d) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
5. (e) Assertion
6. (f) is true, but Reason (R) is false.
7. (g) Assertion
8. (h) is false, but Reason (R) is true.

2026Very short answer·2 marks·Q33(B)Magnetic field due to a current through a straight conductor

How is an electromagnet made? Write any two ways by which the strength of electromagnet can be increased.

2026Short answer·3 marks·Q37Force on a current-carrying conductor and Fleming's left-hand rule

On the basis of the given circuit arrangement, answer the following questions: (a) What happens to the rod AB when the key K is closed and why? (b) Name and state the rule that determines this behaviour of the rod AB in the above situation.

2026Very short answer·2 marks·Q11Food chains and food webs

Explain why food chains generally consist of three or four steps.

2026Assertion-Reason·1 mark·Q9Food chains and food webs

Assertion (A): Highest percentage of pesticides is found in tertiary consumers in a food chain. Reason (R): Chemicals / pesticides get accumulated progressively at each trophic level.

1. (a) Both Assertion
2. (b) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
3. (c) Both Assertion
4. (d) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
5. (e) Assertion
6. (f) is true, but Reason (R) is false.
7. (g) Assertion
8. (h) is false, but Reason (R) is true.

2026MCQ·1 mark·Q3Managing the garbage we produce

Given below are some of the statements regarding our environment: (i) Change in our life-styles have resulted in greater amounts of waste material generation. (ii) Changes in attitude have resulted in use of more disposable things. (iii) Changes in packaging has resulted in much of our waste becoming non-biodegradable. (iv) Organic farming. Which amongst these is not leading to any damage of environment?

1. (a) (i), (ii), (iii)
2. (b) (iv)
3. (c) (i) and (iii)
4. (d) (ii) and (iv)