CBSE(NCERT) GRADE 10 SCIENCE 2025 COMPARTMENT SET3

Application of Abscisic acid on plants promotes:

The part of the hindbrain present immediately above the medulla is :

Consider the following cases : (i) $\mathrm{CaSO_4 + Mg}$ (ii) $\mathrm{CuSO_4 + Ca}$ (iii) $\mathrm{ZnSO_4 + Fe}$ (iv) $\mathrm{FeSO_4 + Zn}$ The cases in which new products will form, are :

The number of single and double bonds present in a molecule of benzene ($\mathrm{C_6H_6}$) respectively, are :

The most malleable metals are :

Breakdown of proteins in the stomach takes place by the enzyme :

Select exothermic processes from the following : (i) Dilution of acid (ii) Burning of natural gas (iii) Evaporation of water (iv) Electrolysis of water

From the following, select a process in which combination reaction occurs :

The unit of heredity is :

The end product of meiosis in a reproductive cell in plants is :

Which one of the following statements is incorrect about the effect on our environment as a result of our activities ?

In a food chain existing in a grassland, the organism(s) occupying the fourth trophic level are:

The organism occupying the fourth trophic level in a food chain operating in grassland is :

In a series of bottles, the image formed by a plane mirror is :

The strength of the magnetic field inside a current carrying long straight solenoid is :

Which of the following factors affects the electrical resistance of a conductor ?

Which of the following atomic orbitals always forms $m = +1$ ?

An optical device which always produces images of m = + 1 is :

Refractive index of diamond with respect to glass is 1·6. If the absolute refractive index of glass is 1·5, the absolute refractive index of diamond is :

Assertion (A) : Due to scattering of sunlight, the clear sky predominantly appears blue. Reason (R) : The wavelength of blue light is nearly 1·8 times the wavelength of red light.

Assertion (A) : In our homes we receive supply of electric power through a main supply. One of the wires in this supply, usually with red insulation, is called live wire and another wire with green insulation is called neutral wire. Reason (R) : In our country, the potential difference between the live wire and the neutral wire is 220 volts.

Assertion (A) : Decomposition of vegetable matter into compost is an exothermic reaction. Reason (R) : Decomposition reactions need energy to break down the reactants.

Assertion (A) : Transpirational pull helps

Assertion (A): Transpirational pull helps in the absorption and upward movement of water and dissolved minerals in plants. Reason (R): The effect of root pressure in transport of water is more significant at night.

(a) (i) What is an alloy ? (ii) Write the composition of solder and the property which makes it suitable for welding electric wires. OR (b) During electrolytic refining of silver: (i) What are the electrodes – cathode and anode made up of ? (ii) What is anode mud ? Why is it called so ?

Translate the following statements into balanced chemical equations: (a) Aluminium reacts with copper chloride to form aluminium chloride and copper. (b) Zinc reacts with sodium hydroxide to give sodium zincate and hydrogen gas.

How is the small intestine in humans designed to absorb the digested food ?

Draw a ray diagram to show the path of a ray of light which falls obliquely on one of the faces of an equilateral triangular prism made of glass and mark on it the angle of incidence ($\angle i$) and the angle of deviation ($\angle D$).

An object is placed 25 cm in front of a concave mirror of focal length 15 cm. Use mirror formula and new cartesian sign convention to determine the position of the image formed.

(a) Explain how tendrils help a pea plant climb up other plants or fences. OR (b) List two major limitations of the use of electrical impulses as a means of communication between the cells in most multicellular animals.

(a) Define the term biological magnification. (b) In the given aquatic food chain, which trophic level will have highest effect of biological magnification and why? Phytoplankton → Zooplankton → Fishes → Human

You have two solutions ‘X’ and ‘Y’. ‘X’ gives red colour and ‘Y’ gives blue colour with universal indicator. (a) In which solution is the hydrogen ion concentration more than the other? Give reason to justify your answer. (b) If ‘X’ and ‘Y’ are mixed in proper amounts and the resultant mixture of ‘X’ and ‘Y’, with the universal indicator turns green, what would be the nature of the resultant mixture? Justify your answer.

Name the parts ‘X’ and ‘Y’ of human brain in the given diagram and give one function of each. ‘X’ ‘Y’

(a) Write the name and chemical formula of a sodium compound which is sometimes added for faster cooking. How is it produced from sodium chloride as one of the raw materials? Give chemical equation for the reaction involved. (b) The compound mentioned in (a) above is also an ingredient of antacids. Why?

(a) State the Right-hand thumb rule. (b) A steady current flows through a horizontal power line from east to west direction as shown in the figure. Apply right-hand thumb rule to determine the direction of magnetic field (i) at a point directly below it, and (ii) at a point directly above it.

Show the arrangement of three resistors of 2 $\Omega$, 3 $\Omega$ and 6 $\Omega$ which are connected in such a way that the total/equivalent resistance of the combination is (a) 1 $\Omega$, and (b) 4 $\Omega$. Justify your answer in each case.

(a) Explain the process of translocation of food and other substances in the phloem of plants. OR (b) Differentiate between xylem and phloem on the basis of the following : (i) Direction of transport of the substances (ii) Major driving forces involved in the transport (iii) Nature of the substance(s) transported

(a) (i) When hydrochloric acid is added to sodium carbonate, brisk effervescence is observed. Explain this observation with the help of chemical equation. What is the purpose of keeping sodium carbonate in a wash bottle in the laboratory? (ii) If carbon dioxide is passed through lime water, what happens? Write the chemical equation for your answer. OR (b) (i) When dilute hydrochloric acid is added slowly to copper oxide kept in a beaker, the colour of the solution changes. State the colour of the resultant solution. Write the balanced chemical equation for the reaction.

(a) (i) On adding dilute HCl to a test tube containing sodium carbonate, an effervescence is observed. Explain the observation giving chemical equation for the reaction. How is the gas released tested in a school laboratory? (ii) What happens when excess carbon dioxide passes through lime water? Write chemical equations to explain your answer. OR (b) (i) A small amount of copper oxide is taken in a beaker and dilute HCl is added to it slowly. Name the compound formed and state the colour of the solution formed. Write the balanced chemical equation for the reaction that occurs. (ii) A compound ‘X’ on heating at 373 K, loses water molecules and becomes ‘Y’. Substance ‘Y’ is used by doctors for supporting fractured bones in the right position. I. Identify ‘X’ and ‘Y’. II. How can ‘X’ be obtained from ‘Y’ ?

(a) (i) When and where does a rainbow appear in the sky ? List the phenomena of light which occur during the formation of a rainbow in proper sequence. Draw a labelled diagram to show the formation of a rainbow. (ii) List two conditions to observe a rainbow in the sky. Why can a rainbow not be seen from the surface of the moon? Explain. OR (b) (i) What is hypermetropia ? List its two possible causes. Name the type of lens used to correct this defect and state its role in this case. (ii) A person suffering from presbyopia needs bifocal lens. If he needs two lenses of power + 2·5 D and – 0·25 D, which one of these two lenses is for the correction of distant vision and what is its focal length ?

(a) (i) In which form is the information for inheritance of features transmitted from one generation to the next generation ? (ii) Differentiate between binary fission in Amoeba and Leishmania. (iii) “Fragmentation cannot be a method of reproduction in all multicellular organisms.” Justify this statement.

(b) (i) Define placenta. State the structure and role of placenta in the development of embryo in human beings. (ii) List three categories of contraceptives and give one example of each.

(ii) List two conditions to observe a rainbow in the sky. Why can a rainbow not be seen from the surface of the moon ? Explain.

(b) (i) What is hypermetropia ? List its two possible causes. Name the type of lens used to correct this defect and state its role in this case. (ii) A person suffering from presbyopia needs bifocal lens. If he needs two lenses of power + 2·5 D and – 0·25 D, which one of these two lenses is for the correction of distant vision and what is its focal length ?

(a) State what happens when 1 (i) only key K 1 is closed, (ii) and key K 2 is also closed. (b) Find the current drawn by the bulb L.

(c) (i) Calculate the resistance of the bulb A. Find the total resistance offered by the circuit to the flow of current when only key K 2 is closed. OR (c) (ii) What would happen to the glow of the bulbs in the circuit when K 1 and K 2 both are closed and the fuse F 1 melts suddenly ? Give reason to justify your answer.

(a) Identify the following compound and write its name. CH3 − C  CH (b) How do saturated and unsaturated carbon compounds differ in terms of the flame produced by them on burning ? (c) (i) Which type of hydrocarbons undergo addition reactions ? Show with an example. OR (c) (ii) What are structural isomers ? Draw two structural isomers of butane ($C_4H_{10}$).

The process of determining the sex of a newborn is purely genetic. But still many people in some societies believe that only the woman (mother) is responsible for determination of the sex of the child and blame her. In fact, the sex of the child is genetically determined. But there are some animals where sex is not genetically determined. (a) Define sex chromosomes. (b) Mention one example of animals where sex is not genetically determined. How is sex determined in these animals? Explain.

Does the genetic combination of the mother play a significant role in determining the sex of newborn? Explain.

How is equal genetic contribution of male and female parents ensured in progeny?