CBSE(NCERT) GRADE 10 SCIENCE 2025 COMPARTMENT SET4

Select from the following decomposition reactions in which the source of energy for decomposition is heat:

The number of covalent bond(s) present in a nitrogen molecule is/are: (Atomic number of nitrogen is 7)

Consider the reactions of dil. hydrochloric acid with the following metals: Aluminium, Copper, Iron, Magnesium and Zinc. The correct observation is:

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

Oxides of aluminium and zinc are:

Application of Abscisic acid on plants promotes:

The valves in the human heart ensure that: (i) Oxygen-rich blood flows from left atrium to left ventricle only. (ii) Deoxygenated blood flows from left atrium to left ventricle only. (iii) Oxygen-rich blood flows from right atrium to right ventricle only. (iv) Deoxygenated blood flows from right atrium to right ventricle only.

The valves in the human heart ensure that:

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

In garden pea, violet colour flower is the dominant trait over white colour flower which is the recessive trait. When parent plant with violet coloured flowers $(Vv)$ is crossed with a parent plant with white flowers, the possible percentage of occurrence of traits in the F1 progeny would be:

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

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

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

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

Which one of the following factors affects the electrical resistivity of a conductor?

Concave mirror finds its application in which of the following cases?

In an ecosystem, 10% of energy available for transfer from one trophic level to the next in a food chain is in the form of:

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): 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): 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.

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 ($\angle D$).

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.

(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?

Explain how circulation of blood takes place in fishes.

An object is placed 18 cm in front of a concave mirror of focal length 12 cm. Use mirror formula to determine the position of the image formed in this case.

(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.

As shown in the figure a small aluminum rod AB is suspended horizontally between the poles of a strong horseshoe magnet. This rod is also connected with a battery and a key. Study the arrangement shown. (a) State Fleming’s left-hand rule. (b) Apply Fleming’s left-hand rule to determine : (i) What is observed when a current is passed from B to A in the rod ? (ii) What is observed when a current is passed from A to B in the rod ? (iii) What is observed when the rod AB is aligned parallel to the magnetic field and current is passed through it from B to A ? Justify your answer in this case.

(a) (i) Differentiate between self-pollination and cross-pollination. (ii) Explain the events taking place in a flower after a pollen lands on a suitable stigma, till fruit-formation. OR (b) (i) What is the site of fertilisation of egg in a female reproductive tract ? (ii) Fertilised egg on implantation in uterus lining continues to grow and develop to become a foetus. Explain how it gets nourishment and removes metabolic wastes during this period.

(a) (i) Define the term power of accommodation of human eye. What happens to the image distance in the eyes when the distance of an object is increased gradually from about 5 m to 500 m from our eyes ? Name and explain the role of the part of human eye responsible for it in this case. (ii) A person is unable to see distinctly the objects placed beyond 2 m from his eyes. Name the defect of vision the person is suffering from. List two possible causes of this defect and write the type of lenses used for the correction of this defect. OR (b) (i) Name and explain the phenomenon of light responsible to make the path of a beam of light visible when it enters a smoke/dust-filled room through a small hole. Also state the dependence of the colour of the light we receive on the size of the particles of the medium through which the light passes.

(ii) A person is suffering from a defect of vision and uses spectacles with lens powers of +2.0 D and −0.5 D. Which lens is used for seeing distant objects clearly and what is its focal length ?

A person is unable to see distinctly the objects placed beyond 2 m from his eyes. Name the defect of vision the person is suffering from. List two possible causes of this defect and write the type of lenses used for the correction of this defect.

(b) (i) Name and explain the phenomenon of light responsible to make the path of a beam of light visible when it enters a smoke/dust-filled room through a small hole. Also state the dependence of the colour of the light we receive on the size of the particles of the medium through which the light passes.

(a) (i) State the relation between hydrogen ion concentration and its pH. (ii) Why is the process of dilution carried out when a concentrated acid is mixed with water? (iii) Why do hydrochloric acid and acetic acid of the same concentration, in equal volumes, produce different amounts of hydrogen ions?

(ii) A person suffering from presbyopia needs spectacles having bifocal lenses. If the power of two lenses used in his spectacles is +2.0 D and −0.5 D, which one of the two lenses is for the correction of his distant vision and what is its focal length ?

(a) (i) Give the relation between hydrogen ion concentration of an aqueous solution and its pH. (ii) Concentrated acids should not be diluted by adding water to acid. Why ? (iii) Why do same molar concentrations of hydrochloric acid and acetic acid not produce same amounts of hydrogen ions ?

(b) Give reason : 5×1=5 (i) Crystals of washing soda change to white powder on exposure to air. (ii) Plaster of Paris should be stored in moisture-proof containers. (iii) Baking soda can be used on bee sting area to get relief. (iv) Distilled water does not conduct electricity. (v) Farmers treat the soil of their fields with quick lime.

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. 1 (b) Mention one example of animals where sex is not genetically determined. How is sex determined in these animals ? Explain. 1 (c) (i) Does the genetic combination of the mother play a significant role in determining the sex of newborn ? Explain. 2 OR (c) (ii) How is equal genetic contribution of male and female parents ensured in progeny ? 2

(a) Define sex chromosomes. (b) Mention one example of animals where sex is not genetically determined. How is sex determined in these animals? Explain. (c) (i) Does the genetic combination of the mother play a significant role in determining the sex of newborn? Explain. OR (c) (ii) How is equal genetic contribution of male and female parents ensured in progeny?

In a domestic circuit, six LED bulbs and a ceiling fan are arranged as per the circuit shown in the figure. The source voltage is 220 volts and the power rating of each device is marked in the circuit diagram. Two fuses $F_1$ and $F_2$ are also provided in the circuit. Based on the circuit diagram, answer the following questions: (a) State what happens when (i) only key $K_1$ is closed, (ii) 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.

All compounds of carbon which contain only carbon and hydrogen are called hydrocarbons. Among these, saturated hydrocarbons are called ‘alkanes’, unsaturated compounds with one or more double bonds are called ‘alkenes’ and compounds containing one or more triple bonds are called ‘alkynes’. (a) Identify the following compound and write its name. $\mathrm{CH_3 - C \equiv CH}$ (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 ($\mathrm{C_4H_{10}}$).