NCERT Solutions for Class 10 Science

NCERT Solutions for Class 10 Science all chapters in PDF form to free download or view online free of cost. All the NCERT Solutions and Offline Apps 2020-21 are updated for current academic session 2020-2021.

These NCERT Solutions are free for CBSE board, MP, Bihar board, UP Board, Gujrat Board, Uttarakhand Board, MP Board (Madhya Pradesh Board who are following CBSE Syllabus 2020–21. For UP board (High School) students, these solutions are given in Hindi Medium as well as English medium. NCERT Solutions for class 10 Science are available in Hindi & English in both the format whether on website or in Offline apps.

NCERT Solutions for Class 10 Science

Subject:Science -विज्ञान
Medium:English – हिन्दी

CBSE NCERT Solutions for Class 10 Science

NCERT Solutions for Class 10 Science in English Medium as well as Hindi Medium free to download in PDF or study online free. All the solutions are updated for new academic session 2020-21. Students of UP Board, MP Board, Gujrat Board and all other boards can use these solutions who are following latest CBSE Syllabus 2020-21.

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We are planning to upload important questions from Lakhmir Singh & Manjeet Kaur, U – Like, Exam Idea and other popular books for academic session 2020-21. We are also making a separate section for CBSE Board Questions which include previous year questions and questions form CBSE sample papers. NCERT of all chapters (Physics, Chemistry and Biology) are given in the section of solution. Important derivations, numerical problems, practice test and assignments will also have uploaded time to time. To get updates, check the web page once a week or monthly. Through holiday homework page you can upload you summer holiday, if need help, we will provide the solutions and suggestions according to requirements. Offline Solutions Apps works without Internet. On this website, there is no need to login or registration to use the contents.

Important Questions on 10th Science

Why is respiration considered an exothermic reaction? Explain.
Energy in our body is obtained from the food we eat. During digestion, large molecules of food are broken down into simpler substances such as glucose. Glucose combines with oxygen in the cells and provides energy. The special name of this combustion reaction is respiration. Since energy is released in the whole process, it is an exothermic process.
What are olfactory indicators? Give an example.
Olfactory indicators are substances which have different odour in acid and base solutions. For example, vanilla essence has characteristics pleasant smell in acid solution and no smell in alkali solution.
Platinum, gold and silver are used to make jewellery. Why?
Platinum, gold, and silver are used to make jewellery because they are very lustrous. Also, they are very less reactive and do not corrode easily.
Why are carbon and its compounds used as fuels for most applications?
Most of the carbon compounds give a lot of heat and light when burnt in air. Saturated hydrocarbons burn with a clean flame and no smoke is produced. The carbon compounds, used as a fuel, have high calorific values. Therefore, carbon and its compounds are used as fuels for most applications.
How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?
In the modern periodic table, atoms with similar electronic configurations are placed in the same column. In a group, the number of valence electrons remains the same. Elements across a period show an increase in the number of valence electrons.
What is the role of saliva in the digestion of food?
Saliva is secreted by the salivary glands, located under the tongue. It makes the food soft for easy swallowing. It contains a digestive enzyme called salivary amylase, which breaks down starch into sugar.
What are the methods used by plants to get rid of excretory products?
Plants use completely different strategies for excretion than those of animals. They can get rid of excess water by transpiration. For other wastes, plants use the fact that many of their tissues consist of dead cells, and that they can even lose some parts such as leaves. Many plant waste products are stored in cellular vacuoles. Waste products may be stored in leaves that fall off. Other waste products are stored as resins and gums, especially in old xylem. Plants also excrete some waste substances into the soil around them.
How does phototropism occur in plants?
The movement of plant in response to light is called phototropism. Stem shows positive phototropism as follows: When growing plants detect light, a hormone called auxin, synthesised at the shoot tip, helps the cells to grow longer. When light is coming from one side of the plant, auxin diffuses towards the shady side of the shoot. This concentration of auxin stimulates the cells to grow longer on the side of the shoot which is away from light. Thus, the plant appears to bend towards light.
How does chemical coordination take place in animals?
Chemical coordination takes place in animals with the help of hormones. Hormone is the chemical messenger that regulates the physiological processes in living organisms. It is secreted by glands. The regulation of physiological processes and control and coordination by hormones comes under the endocrine system. The nervous system along with the endocrine system in our body controls and coordinates the physiological processes.
How does the process of budding is differ from the process of spore formation?
Budding: A bud, as in Hydra, develops as an outgrowth due to replicated cell division at a specific site. These buds when mature detach from the parent body and become new individual.
Spore Formation: In spore formation, as in Rhizopus, a specific part called Sporangia that produce spores. The spores are covered by thick walls that protect them until a spore gets favourable conditions to grow into a new (Rhizopus) plant.
Explain how sexual reproduction gives rise to more viable variations than asexual reproduction. How does this affect the evolution of those organisms that reproduce sexually?
In sexual reproduction, two individuals having different variations combine their DNA to give rise to a new individual. Therefore, sexual reproduction allows more variations, whereas in asexual reproduction, chance variations can only occur when the copying of DNA is not accurate. Additionally, asexual reproduction allows very less variations because if there are more variations, then the resultant DNA will not be able to survive inside the inherited cellular apparatus.
However, in sexual reproduction, more variations are allowed and the resultant DNA is also able to survive, thus making the variations viable.
Variation and Evolution: Variants help the species to survive in all the conditions. Environmental conditions such as heat, light, pests, and food availability can change suddenly at only one place. At that time, only those variants resistant to these conditions would be able to survive. This will slowly lead to the evolution of a better adapted species. Thus, variation helps in the evolution of sexually reproducing organisms.
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not?
Geographical isolation prevents gene flow between populations of a species whereas asexual reproduction generally involves only one individual. In an asexually reproducing organism, variations can occur only when the copying of DNA is not accurate. Therefore, geographical isolation cannot prevent the formation of new species in an asexually reproducing organism.
Name the mirror that can give an erect and enlarged image of an object.
When an object is placed between the pole and the principal focus of a concave mirror, the image formed is virtual, erect, and enlarged.
A battery of 9 V is connected in series with resistors of 0.2 Ω, 0.3 Ω, 0.4 Ω, 0.5 Ω and 12 Ω, respectively. How much current would flow through the 12 Ω resistor?
Total resistance of resistors when connected in series is given by
R = R1 + R2 + R3 + R4 + R5 = ⟹ R= 0.2 Ω + 0.3 Ω + 0.4 Ω + 0.5 Ω + 12 Ω =13.4 Ω
According to Ohm’s law, V = IR

I = V/R = 9/13.4 = 0.67 A

There is no current division occurring in a series circuit. So, the current through the 12 Ω resistor will be same as 0.67 A.

Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
The resistivity of an alloy is higher than the pure metal and it does not corrode easily. Moreover, even at high temperatures, the alloys do not melt readily. Hence, the coils of heating appliances such as electric toasters and electric irons are made of an alloy rather than a pure metal.
When is the force experienced by a current–carrying conductor placed in a magnetic field largest?
The force experienced by a current-carrying conductor placed in a magnetic field is largest when the current-carrying conductor is placed in a direction perpendicular to that of magnetic field.
What is the role of the split ring in an electric motor?
The split ring in the electric motor acts as a commutator. The commutator reverses the direction of current flowing through the coil after each half rotation of the coil. Due to this reversal of the current, the coil continues to rotate in the same direction.
What is a good source of energy?
A good source of energy should have the following qualities:
It should be easily available.
It should do a large amount of work (or produce large amount of heat) per unit volume/mass.
It should be easy to store and transport.
It should be economical.
It should cause less environmental pollution.
What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
Progressive increase in the concentration of non-biodegradable substances in a food chain is called biological magnification. The level of these harmful substances will go on increasing from one trophic level to the next. When certain harmful substances enter the food chain at the level of primary producers,-they get concentrated many times at each subsequent trophic level.
What can you as an individual do to reduce your consumption of the various natural resources?
Save electricity.
Do not waste food.
Save water.
Use cooking gas instead of wood for cooking.
Observe the principle of three R’s (Reduce, Recycle and Reuse).