CBSE(NCERT) GRADE 10 SCIENCE 2023 COMPARTMENT SET2

In the electrolysis of water, if the mass of the gas collected at the anode is $m_a$ and the mass of the gas collected at the cathode is $m_c$, the value of $(m_c/m_a)$ is :

Consider the following substances : (i) Acidified $K_2Cr_2O_7$ (ii) Alkaline $KMnO_4$ (iii) Oxygen (iv) Hydrogen Out of these, the commonly used oxidising agents are :

Select from the following compounds which is not a base :

2 g of yellow sulphur powder is burnt in a china dish and the fumes

2 g of yellow sulphur powder is burnt in a china dish and the fumes are collected in a test tube. Water is added in the test tube and the solution is tested separately with blue and red litmus paper. The correct option is:

Which one of the following metals is malleable and a poor conductor of electricity?

You want to test for hardness of water but hard water is not available in the laboratory. Which of the following compounds may be dissolved in pure water to make it hard? (i) Hydrogen Carbonate of Sodium (ii) Sulphate of Magnesium (iii) Chloride of Calcium (iv) Carbonate of Sodium

Which one of the following properties of Carbon is not responsible for its formation of large number of compounds?

Which one of the following molecules is produced initially when glucose breaks down in the cytoplasm of a cell in aerobic as well as anaerobic respiration?

As compared to daytime, the amount of carbon dioxide released by the plants during night is more because:

The organism in which an outgrowth on the parent body develops into a new individual is :

In a cross between pure tall pea plants (TT) and pure dwarf pea plants (tt) the offsprings of F1 generation were all tall. When F1 generation was self-crossed, the gene combinations of the offsprings of F2 generation will be :

When an object is placed beyond 2F of a convex lens, the nature of the image formed is :

When a narrow beam of white light passes through a glass prism it splits into its component colours ? This phenomenon is called :

A material used for making heating elements of electrical heating devices should have :

The resistance of a wire does not depend on its :

The shape of magnetic field lines produced (i) inside a solenoid (ii) around a straight conductor, both carrying current of the same magnitude are, respectively :

For Questions number 17 to 20, two statements are given one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below. (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A). (b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A). (c) Assertion (A) is true, but Reason (R) is false. (d) Assertion (A) is false, but Reason (R) is true. Assertion (A) : In the reaction, Na2SO4 + BaCl2 BaSO4 + 2NaCl, sodium chloride is precipitated. Reason (R) : When an aqueous solution is added to another aqueous solution, an insoluble substance is formed, which is called precipitate.

Assertion (A): In the reaction, $\mathrm{Na_2SO_4 + BaCl_2 \rightarrow BaSO_4 + 2NaCl}$, sodium chloride is precipitated. Reason (R): When an aqueous solution is added to another aqueous solution, an insoluble substance is formed, which is called precipitate.

Assertion (A): A hormone called abscisic acid inhibits growth in plants. Reason (R): The role of auxins is opposite to that of abscisic acid in plants.

Assertion (A): Each human trait is influenced by both paternal and maternal DNA. Reason (R): As compared to the father, the mother contributes more amount of genetic material to the child.

Assertion (A): A rainbow is an artificial spectrum of white light appearing in the sky after a rain shower. Reason (R): The water droplets act like small prisms.

(a) A metal reacts vigorously with cold water and gives off gas. Another metal when dipped in water starts floating. A metal does not react with cold or hot water but reacts with steam. A metal does not react with water in any way. Identify the metals A, B, C and D. OR (b) When two compounds namely sodium chloride and calcium chloride are heated directly, one by one on the flame of a burner, they impart different colours to the flame. (i) Name the colour imparted by (1) sodium chloride and (2) calcium chloride. (ii) Are these compounds soluble in organic solvents such as kerosene or petrol? Justify your answer.

Name the glands which add their secretions to the sperms. List two functions of these secretions.

In human beings, the sex of a new born child depends on the father, not on the mother. Justify this statement with the help of a flow chart.

(a) Find the magnification of the image formed by a spherical mirror from the following data: $u = 20\ \mathrm{cm}$, $f = 15\ \mathrm{cm}$. OR (b) Draw a labelled ray diagram for the image formation by a concave mirror when an object is placed between its centre of curvature and focus.

What will happen if an electric oven of rating $3\ \mathrm{kW};\ 220\ \mathrm{V}$ is operated in a domestic electric circuit ($220\ \mathrm{V}$) that has a current rating of $10\ \mathrm{A}$? Give reason with your answer.

What is photosynthesis ? Name the organelle and the organs in which photosynthesis takes place. Where does the oxygen liberated come from during this process ? What happens to the carbohydrates which are not immediately used by the plant ?

Find the magnification of the image formed by a spherical mirror from the following data : $u = 20$ cm, $f = 15$ cm.

Draw a labelled ray diagram for the image formation by a concave mirror when an object is placed between its centre of curvature and focus.

(a) Give the structure and function of alveoli in human respiratory system. (b) What is meant by residual volume of air in the lungs ?

State any one advantage of using cloth bags over plastic bags.

Write any two ways by which plants obtain carbon dioxide. What causes the opening and closing of the stomata ?

List any two methods by which the solid wastes generated in urban areas can be safely disposed off.

What is Tyndall effect ? Give two examples where this phenomenon is observed. Give reason to explain this phenomenon.

(a) (i) Differentiate between a solenoid and a circular coil. (ii) Explain how a solenoid can be made in a school laboratory. (iii) Write one use of the strong magnetic field produced inside a current carrying solenoid. OR (b) With the help of a labelled circuit diagram, illustrate the pattern of the magnetic field lines of the magnetic field produced around a straight current carrying conductor. Explain how, with the help of right-hand thumb rule, we can determine and mark the direction of magnetic field lines due to a current.

An organic compound X when reacts with sodium liberates hydrogen. The same compound X when heated at 443 K in the presence of concentrated sulphuric acid gives an unsaturated hydrocarbon. (i) Identify X (ii) Write the chemical equations for the above mentioned reactions and state the role of concentrated sulphuric acid in the second reaction.

Define trophic levels. At which trophic level do we find (i) secondary and (ii) tertiary consumers in a food chain ? What will happen if all the organisms of a trophic level die ? Give reasons to justify your answer.

(i) Why are carbon compounds exceptionally stable ? (ii) Differentiate between saturated and unsaturated compounds. Give structures of both the types of compounds having three carbon atoms in their molecules.

(a) (i) An aqueous solution turns blue litmus red. Which of the following solutions when added in excess would reverse the change ? (ii) Out of the following, which compound/compounds will turn the phenolphthalein solution pink ? (iii) Name a gas whose aqueous solution is basic. Write the formula/name of this solution. (iv) A basic substance is used to treat a honey-bee sting. Why ? (v) Name the acid which is present in (1) Tomato and (2) Tamarind.

(a) (i) Name the parts in the human female reproductive system where the following functions take place : (1) Maturation of eggs (2) Fusion of the egg and the sperm (3) Implantation of the zygote (ii) What happens to the egg (1) when it is fertilised ? (2) when it is not fertilised ? OR (b) (i) Explain by giving one example each : (1) Unisexual flowers (2) Bisexual flowers (ii) Name the labelled parts A, B, C and D in the diagram given below. (iii) justify this statement.

(a) The commercial unit of electric energy is commonly known as _____. State its actual name and establish the relationship between this unit and the SI unit of energy. (b) The current rating of a circuit is $1.0\,\text{A}$. How many LED lamps of power rating $8\,\text{W};\ 220\,\text{V}$ can safely be used simultaneously in this circuit ?

The iron pillar in Qutab Minar complex in Delhi was built 1600 years ago. It is still standing intact and shows no signs of rusting even today. This shows that the ancient metallurgists of India in those times had fully developed metallurgical processes as well as the techniques of protection of different metals. The protection of metals, was done by several processes like coating of a thin film of another metal, alloying etc. (a) Where is iron placed in the reactivity series of metals ? Write the form/forms in which its ores are found in nature. (b) Differentiate between roasting and calcination. (c) Explain any two methods that are employed to prevent rusting/corrosion of metals. OR (c) Why is aluminium used to join railway tracks or the cracked machine parts of iron ? Write a balanced chemical equation for the reaction which occurs.

In animals the control and coordination is provided by nervous and muscular tissues. Nervous tissue is made of an organized network of nerve cells or neurons. In human beings, thinking is a complex activity which involves more complex mechanisms and neural connections. These are concentrated in the brain which is the main coordinating centre of the human body. The brain and spinal cord constitute the Central Nervous System which receives information from all parts of the body and integrates it. (a) How is the brain protected from shocks and injuries? (b) Write the main functions of (i) sensory neuron and (ii) motor neuron in a reflex arc. (c) Which part of the brain is involved in activities like (i) picking a pencil and (ii) vomiting? State whether these actions are voluntary or involuntary. OR (c) How does the central nervous system communicate with other parts of the body to carry out various activities? Name two components of this system.

When a ray of light moving in a medium enters obliquely into another medium, it bends from its path. This phenomenon is called refraction of light. The ability of a medium to refract light is also expressed in terms of optical density. It is not the same as mass density. We use the terms

(a) Define the term absolute refractive index of a medium. (b) Absolute refractive indices of water and glass are $\frac{3}{4}$ and $\frac{2}{3}$ respectively. (i) In which one of the two media is the speed of light more? (ii) If a ray of light enters obliquely from glass to water, will it bend towards the normal or away from the normal? (c) The absolute refractive indices of water and glass are $\frac{3}{4}$ and $\frac{2}{3}$ respectively. If the speed of light in glass is $2 \times 10^8$ m/s, find the speed of light in (i) water and (ii) vacuum. OR (c) any medium emerges parallel to diagram to justify this statement.

Differentiate between roasting and calcination.

Explain any two methods that are employed to prevent rusting/corrosion of metals.

Why is aluminium used to join railway tracks or the cracked machine parts of iron ? Write a balanced chemical equation for the reaction which occurs.