Important Questions for Science Class 10

Let’s see Important questions for science class 10 for CBSE boards. Science is a crucial subject for students studying in Class 10 as it helps them develop an understanding of the world around them. To score well in the board exams, it is essential to have a clear understanding of the concepts taught in the curriculum. To help students in their preparations, we have compiled a list of chapter-wise important questions for Science Class 10.

Chapter-wise Important Questions for Science Class 10

Click on the link below to access the CBSE class 10 Science important questions. These questions could be asked on the actual board exam. Students should practice these questions thoroughly. Students can clear up their doubts by solving the important questions for CBSE Class 10 Science. This will help them understand their preparation level. These questions can be prepared by looking at CBSE class 10 Science past year question papers, samples papers, and so on.

Some class 10th important questions of science

Here are some Class 10th Important questions of Science. These questions are very important and we have also given detailed solutions for these questions. Also checkout class 10th sst notes.

Chapter 1: Chemical Reactions and Equations

Here are the class 10th important questions of science Chapter Chemical Reactions and Equations:

Explain the difference between physical and chemical changes.
Physical changes involve changes in the physical properties of a substance without changing its chemical composition. Examples of physical changes include melting, freezing, boiling, and condensation. Chemical changes, on the other hand, involve changes in the chemical composition of a substance, resulting in the formation of a new substance with different chemical properties. Examples of chemical changes include rusting of iron, burning of paper, and digestion of food.
What is meant by the balancing of a chemical equation? Give an example.
Balancing a chemical equation means making sure that the same number of atoms of each element is present on both the reactant and product sides of the equation. For example, consider the reaction between hydrogen gas and oxygen gas to form water: 2H2 + O2 -> 2H2O In this equation, the number of hydrogen atoms on the left side is 4 (2×2), while the number of hydrogen atoms on the right side is also 4 (2×2). Similarly, the number of oxygen atoms on the left side is 2, while the number of oxygen atoms on the right side is also 2.
Write the chemical equation for the reaction between magnesium and oxygen.
The reaction between magnesium and oxygen can be represented by the following chemical equation: 2Mg + O2 -> 2MgO In this equation, two atoms of magnesium combine with one molecule of oxygen gas to form two molecules of magnesium oxide.
Explain the difference between endothermic and exothermic reactions.
Endothermic reactions are those that absorb energy from the surroundings, resulting in a decrease in temperature. Examples of endothermic reactions include melting of ice and evaporation of water. Exothermic reactions, on the other hand, release energy into the surroundings, resulting in an increase in temperature. Examples of exothermic reactions include combustion of fuels and formation of rust.

Chapter 2: Acids, Bases, and Salts

Here are the Important Questions for Science Class 10 Chapter Acids, Bases, and Salts:

What is the difference between a strong acid and a weak acid? Give an example.
The main difference between a strong acid and a weak acid is their degree of dissociation in water. Strong acids dissociate completely in water, while weak acids dissociate only partially. This means that strong acids have a higher concentration of H+ ions in solution than weak acids. An example of a strong acid is hydrochloric acid (HCl), while an example of a weak acid is acetic acid (CH3COOH).
Explain the pH scale and its importance in measuring the acidity or basicity of a solution.
The pH scale is a measure of the acidity or basicity of a solution. It ranges from 0 to 14, with 7 being neutral. Solutions with a pH less than 7 are considered acidic, while solutions with a pH greater than 7 are considered basic. The pH scale is logarithmic, which means that a change in one pH unit represents a tenfold change in acidity or basicity. The pH scale is important in measuring the acidity or basicity of a solution because it allows us to quantify the degree of acidity or basicity.
Give two examples of salts that are commonly used in our daily lives.
Two examples of salts that are commonly used in our daily lives are sodium chloride (table salt) and calcium carbonate (used in antacids). Sodium chloride is commonly used as a seasoning and preservative in food, while calcium carbonate is used to neutralize excess stomach acid.
How can you identify a solution as acidic or basic by using a natural indicator like turmeric or litmus paper?
Turmeric or litmus paper can be used to identify whether a solution is acidic or basic. When a natural indicator like turmeric or litmus paper is added to a solution, it changes color depending on the pH of the solution. For example, turmeric paper turns red in the presence of an acidic solution, while it turns yellow in the presence of a basic solution. Similarly, litmus paper turns red in the presence of an acidic solution, while it turns blue in the presence of a basic solution. By comparing the color change with a reference chart, we can determine the pH of the solution.

Chapter 3: Metals and Non-Metals

Here are the class 10th important questions of science Chapter Metals and Non-Metals:

Explain why metals are good conductors of electricity and heat.
Metals are good conductors of electricity and heat because of the presence of free electrons in their structure. These free electrons are able to move easily through the metal, carrying heat and electricity with them. In addition, metals have a closely packed structure with little resistance to the flow of electrons.
Give two examples of metals that are extracted by the reduction of their oxides with carbon.
Two examples of metals that are extracted by the reduction of their oxides with carbon are iron and copper. Iron is extracted by reducing iron oxide with carbon in a blast furnace, while copper is extracted by reducing copper oxide with carbon in a smelting furnace.
Explain why non-metals are not good conductors of electricity.
Non-metals are not good conductors of electricity because they do not have free electrons in their structure. Instead, they have tightly held valence electrons that do not move easily through the material. This makes it difficult for non-metals to carry an electric current.
Write the chemical equation for the reaction between sulphur and oxygen.
The chemical equation for the reaction between sulfur and oxygen is as follows: S + O2 -> SO2 In this equation, sulfur (S) reacts with oxygen (O2) to form sulfur dioxide (SO2). This is an example of a combustion reaction, as oxygen is being used as a reactant to burn the sulfur.

Chapter 4: Carbon and its Compounds

Here are the Important Questions for Science Class 10 Chapter Carbon and its Compounds:

What is the difference between a saturated and unsaturated hydrocarbon?
The main difference between a saturated and unsaturated hydrocarbon is the presence or absence of double or triple bonds between the carbon atoms in the molecule. A saturated hydrocarbon contains only single bonds between the carbon atoms, while an unsaturated hydrocarbon contains one or more double or triple bonds between the carbon atoms.
Write the molecular formula of methane and ethane.
The molecular formula of methane is CH4 and the molecular formula of ethane is C2H6.
Explain the difference between the homologous series and isomerism.
The homologous series is a group of organic compounds that have similar chemical properties and follow a regular pattern of increase in molecular size and complexity. These compounds have the same functional group, the same general formula, and similar chemical reactions. Isomerism is a phenomenon in which two or more organic compounds have the same molecular formula but different structural arrangements of atoms. Isomers have different physical and chemical properties and can exhibit different biological activity.
Write the chemical equation for the reaction between ethanol and acetic acid.
The chemical equation for the reaction between ethanol and acetic acid is as follows: CH3CH2OH + CH3COOH → CH3COOCH2CH3 + H2O In this equation, ethanol (CH3CH2OH) reacts with acetic acid (CH3COOH) to form ethyl acetate (CH3COOCH2CH3) and water (H2O). This is an example of an esterification reaction, in which an alcohol and a carboxylic acid react to form an ester and water.

Chapter 5: Periodic Classification of Elements

Here are the class 10th important questions of science Chapter Periodic Classification of Elements:

Explain the modern periodic law and its significance.
The modern periodic law states that the physical and chemical properties of elements are periodic functions of their atomic numbers. This means that as the atomic number of an element increases, its properties show a periodic pattern, such as increasing or decreasing reactivity, melting point, boiling point, and other physical and chemical properties. The significance of the modern periodic law is that it provides a way to organize the elements and predict their properties based on their position in the periodic table.
What is the difference between the atomic number and the atomic mass of an element?
The atomic number of an element is the number of protons in the nucleus of an atom of that element. It determines the identity of the element and its position in the periodic table. The atomic mass of an element is the average mass of the atoms of that element, taking into account the different isotopes and their relative abundances. It is the sum of the number of protons and neutrons in the nucleus of an atom.
Name the elements in group 1 and group 17 of the periodic table.
The elements in group 1 of the periodic table are called the alkali metals, and they include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). The elements in group 17 of the periodic table are called the halogens, and they include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
What are the properties of metals and non-metals?
The properties of metals include high electrical and thermal conductivity, malleability, ductility, metallic luster, and the ability to form positive ions in chemical reactions. Metals are typically good conductors of heat and electricity, and they tend to lose electrons in chemical reactions to form cations. Non-metals, on the other hand, have low electrical and thermal conductivity, are not malleable or ductile, and tend to gain electrons in chemical reactions to form anions. Non-metals can be solid, liquid, or gas at room temperature, and they are generally not shiny or lustrous.

Chapter 6: Life Processes

Here are the Important Questions for Science Class 10 Chapter Life Processes:

Explain the process of respiration in plants and animals.
Respiration is the process by which living organisms release energy from food to carry out their life processes. In plants, respiration takes place in the cells of the leaves, stems, and roots. The process involves the breakdown of glucose and other organic molecules to release energy in the form of ATP. In animals, respiration takes place in the lungs, and the process involves the exchange of oxygen and carbon dioxide between the blood and the air in the lungs. The oxygen is used to break down glucose in the cells of the body to release energy, which is used for various life processes.
What is meant by the transport of materials in plants? Give an example.
The transport of materials in plants is the process by which water and nutrients are transported from the roots to the leaves and other parts of the plant, while the products of photosynthesis, such as glucose, are transported from the leaves to other parts of the plant. The transport system in plants is made up of xylem and phloem, which are specialized tissues that transport water and nutrients. For example, when a plant is growing, water and nutrients are transported from the roots to the growing parts of the plant, while the products of photosynthesis are transported from the leaves to other parts of the plant, such as the stem and roots.
What is digestion? Explain the process of digestion in humans.
Digestion is the process by which food is broken down into smaller molecules that can be absorbed into the body and used for energy and other life processes. In humans, digestion begins in the mouth, where food is chewed and mixed with saliva, which contains enzymes that break down carbohydrates. The food then passes through the esophagus and into the stomach, where it is mixed with stomach acid and enzymes that break down proteins. The partially digested food then passes into the small intestine, where enzymes from the pancreas and liver break down carbohydrates, proteins, and fats. The nutrients are then absorbed into the bloodstream and transported to the cells of the body for energy and other life processes.
Explain the importance of excretion in living organisms.
Excretion is the process by which waste products are eliminated from the body. This is an important process in living organisms because it helps to maintain the balance of chemicals in the body and prevent the buildup of toxic substances. In humans, excretion occurs through various organs, such as the kidneys, which filter waste products from the blood and eliminate them in the form of urine. The skin also plays a role in excretion, by eliminating waste products through sweat. The liver also plays a role in excretion, by breaking down and eliminating toxins from the body.

Chapter 7: Control and Coordination

Here are the class 10th important questions of science Chapter Control and Coordination:

What is the role of the nervous system in controlling and coordinating the body’s activities?
The nervous system is responsible for controlling and coordinating the body’s activities. It is made up of the brain, spinal cord, and nerves that extend throughout the body. The nervous system receives and processes information from the environment, and sends signals to the muscles and other organs to produce a response. For example, when you touch a hot stove, the nervous system detects the heat and sends a signal to the muscles to move your hand away from the stove.
What is a reflex action? Give an example.A reflex action is an automatic response to a stimulus that occurs without conscious thought. The stimulus is detected by sensory receptors in the body, which send a signal to the spinal cord. The spinal cord then sends a signal to the muscles to produce a response, bypassing the brain. An example of a reflex action is the knee-jerk reflex, in which the knee jerks in response to a tap on the patellar tendon.
Explain the difference between the voluntary and involuntary actions of the body.
Voluntary actions are actions that are under conscious control, such as walking, talking, and writing. These actions are controlled by the motor cortex in the brain, which sends signals to the muscles to produce the desired movement. Involuntary actions are actions that occur without conscious control, such as the beating of the heart and the digestion of food. These actions are controlled by the autonomic nervous system, which regulates bodily functions such as breathing, digestion, and heart rate.
Explain the role of hormones in the human body.
Hormones are chemical messengers that are produced by glands in the endocrine system and are released into the bloodstream. They travel to target organs and tissues, where they produce a specific response. Hormones play a key role in regulating various bodily functions, such as growth and development, metabolism, and reproduction. For example, the hormone insulin is produced by the pancreas and helps to regulate the levels of glucose in the bloodstream. The hormone estrogen is produced by the ovaries and helps to regulate the menstrual cycle and prepare the body for pregnancy.

Chapter 8: How do Organisms Reproduce?

Here are the Important Questions for Science Class 10 Chapter How do Organisms Reproduce:

What is the difference between asexual and sexual reproduction?
Asexual reproduction is the process of producing offspring from a single parent, without the involvement of gametes (sex cells) or fertilization. Sexual reproduction is the process of producing offspring from the fusion of gametes from two parents.
Give examples of organisms that reproduce asexually and sexually.
Examples of organisms that reproduce asexually include bacteria, yeast, and hydra. Examples of organisms that reproduce sexually include humans, dogs, and birds.
What is fertilization? Explain the process of fertilization in humans.
Fertilization is the process by which a sperm cell fuses with an egg cell to form a zygote. In humans, fertilization occurs in the fallopian tubes, where the sperm and egg meet. The sperm penetrates the egg and releases its genetic material, which fuses with the genetic material of the egg to form a zygote. The zygote then undergoes mitosis to form an embryo.
What are the advantages and disadvantages of sexual and asexual reproduction?
The advantages of asexual reproduction include that it is a quick and efficient way to produce offspring, and that it can be done without the need for a mate. The disadvantages include that it does not produce genetic variation, so the offspring are genetically identical to the parent. The advantages of sexual reproduction include that it produces genetic variation, which can help organisms adapt to changing environments. The disadvantages include that it is a slower and more complex process, and that it requires the production of gametes and the finding of a mate.

Chapter 9: Heredity and Evolution

Here are the class 10th important questions of science Chapter Heredity and Evolution:

What is meant by the term ‘heredity’?
Heredity refers to the passing of traits or characteristics from one generation to the next. These traits can be physical, such as eye color or height, or they can be related to behavior, such as temperament or intelligence.
Explain the role of genes in determining the characteristics of an organism.
Genes are segments of DNA that contain the instructions for making proteins, which are the building blocks of the body. Genes determine an organism’s traits by controlling the development and function of its cells and tissues. Each individual has two copies of each gene, one inherited from each parent. The combination of these genes determines an individual’s traits.
What is the difference between acquired and inherited traits?
Inherited traits are traits that are passed down from parents to offspring through their genes, while acquired traits are traits that an individual develops over the course of their life in response to their environment. For example, eye color is an inherited trait, while the ability to play an instrument is an acquired trait.
What is the theory of evolution? Explain the contributions of Charles Darwin to the theory of evolution.
The theory of evolution is the scientific explanation for the diversity of life on Earth, and it states that all living things have descended from a common ancestor through a process of gradual change over time. Charles Darwin was a British naturalist who is best known for his contributions to the theory of evolution. He is famous for his book “On the Origin of Species,” which proposed the idea of natural selection as a mechanism for evolution. Darwin observed that individuals in a population vary in their traits, and that those individuals with traits that are best suited to their environment are more likely to survive and reproduce. Over time, these advantageous traits become more common in the population, while less advantageous traits become less common. This process of natural selection leads to the evolution of new species over time.

Chapter 10: Light – Reflection and Refraction

Here are the Important Questions for Science Class 10 Chapter Reflection and Refraction:

What is the difference between reflection and refraction?
Reflection and refraction are both processes that occur when light interacts with a surface or material. Reflection occurs when light bounces off a surface, while refraction occurs when light passes through a material and changes direction.
Explain the working principle of a periscope.
A periscope is an optical instrument that is used to view objects that are not in the direct line of sight. It consists of two mirrors or prisms that are angled to reflect light in a way that allows the viewer to see around obstacles. The mirrors or prisms are aligned parallel to each other, and the viewer looks into one end while the other end is aimed at the object of interest.
Define the terms: angle of incidence, angle of reflection, and angle of refraction.
The angle of incidence is the angle between the incident ray of light and the normal, or perpendicular, line to the surface it strikes. The angle of reflection is the angle between the reflected ray of light and the normal line. The angle of refraction is the angle between the refracted ray of light and the normal line when light passes through a material with a different refractive index.
What is the difference between a concave and a convex lens?
Concave and convex lenses are two types of lenses that are used to bend and focus light. A concave lens is thinner in the middle than at the edges, and it causes light rays to diverge or spread out. A convex lens is thicker in the middle than at the edges, and it causes light rays to converge or come together at a point. Concave lenses are used to correct nearsightedness, while convex lenses are used to correct farsightedness.

Chapter 11: Human Eye and Colourful World

What is the function of the iris in the human eye?
The iris is the colored part of the human eye that surrounds the pupil. Its function is to control the amount of light that enters the eye by changing the size of the pupil. The iris can expand or contract in response to changes in lighting conditions, allowing more or less light to enter the eye.
Explain the process of accommodation of the eye.
Accommodation is the process by which the lens of the eye changes shape to focus on objects at different distances. The ciliary muscles in the eye contract or relax, causing the lens to become more or less curved, which adjusts the focal length of the lens.
What is the difference between myopia and hyperopia?
Myopia and hyperopia are both refractive errors of the eye that affect the ability to focus on objects at different distances. Myopia, also known as nearsightedness, occurs when the eyeball is too long or the lens is too curved, causing distant objects to appear blurry. Hyperopia, also known as farsightedness, occurs when the eyeball is too short or the lens is too flat, causing close objects to appear blurry.
What is meant by dispersion of light? Explain the phenomenon of a rainbow.
Dispersion of light refers to the separation of white light into its component colors, which occurs because different colors of light travel at different speeds through a medium. The phenomenon of a rainbow is caused by dispersion of light by water droplets in the air, which act like prisms to separate the colors of light. The colors of the rainbow are red, orange, yellow, green, blue, indigo, and violet, in that order.

Chapter 12: Electricity

What is an electric current? Give its SI unit.
An electric current is the flow of electric charge through a conductor. Its SI unit is ampere (A).
What is the difference between a conductor and an insulator?
A conductor is a material that allows electric current to flow through it easily, while an insulator is a material that does not allow electric current to flow through it easily.
Define Ohm’s law and explain its applications.
Ohm’s law states that the current passing through a conductor between two points is directly proportional to the voltage across the two points, and inversely proportional to the resistance between them. Mathematically, Ohm’s law can be expressed as I = V/R, where I is the current, V is the voltage, and R is the resistance. Ohm’s law is used in designing and analyzing electrical circuits, and in determining the value of resistors needed to obtain a specific current or voltage.
What is an electric fuse? Why is it important in electrical circuits?
An electric fuse is a safety device that is placed in an electrical circuit to protect it from overloading and short circuits. It consists of a wire or filament that melts and breaks the circuit when too much current flows through it. This helps to prevent damage to the electrical equipment and reduces the risk of electrical fires.

Chapter 13: Magnetic Effects of Electric Current

Here are the Important Questions for Science Class 10 Chapter Magnetic Effects of Electric Current:

What is a magnetic field? How is it produced?
A magnetic field is a region around a magnet or a current-carrying conductor in which a magnetic force is experienced. It is produced by the motion of electric charges or magnetic materials.
Explain the right-hand thumb rule.
The right-hand thumb rule is a simple way to determine the direction of the magnetic field around a current-carrying conductor. It states that if the right hand is wrapped around the conductor with the thumb pointing in the direction of the current, then the fingers will curl in the direction of the magnetic field.
What is the difference between an electromagnet and a permanent magnet?
An electromagnet is a magnet that is created by passing an electric current through a coil of wire wrapped around a magnetic core, such as iron. It can be turned on and off by controlling the flow of electricity, and its strength can be adjusted. A permanent magnet is a magnet that has a magnetic field that is always present, without the need for an external energy source. Its strength cannot be easily adjusted.
What is meant by the magnetic effect of electric current?
The magnetic effect of electric current refers to the phenomenon in which an electric current flowing through a conductor produces a magnetic field around it. This is the principle behind the working of electric motors, generators, and other electrical devices that utilize the interaction between electric and magnetic fields.

Chapter 14: Sources of Energy

What are the different sources of energy?
There are different sources of energy, including:
1. Fossil fuels, such as coal, oil, and natural gas
2. Nuclear energy
3. Renewable sources of energy, such as solar energy, wind energy, hydropower, geothermal energy, and biomass.
Explain the principle of working of a hydroelectric power plant.
The principle of working of a hydroelectric power plant involves converting the potential energy of water stored in a reservoir into kinetic energy, which can then be used to generate electricity. This is done by channeling the water through a turbine, which is connected to a generator. As the water flows through the turbine, it causes the turbine blades to rotate, which then generates electricity. The amount of electricity generated depends on the flow rate of the water and the size of the turbine and generator.
What is the difference between renewable and non-renewable sources of energy?
Renewable sources of energy are those that can be replenished over time, such as solar energy, wind energy, hydropower, geothermal energy, and biomass. Non-renewable sources of energy are those that are finite and will eventually run out, such as fossil fuels and nuclear energy.
What is the role of solar energy in our daily lives?
Solar energy plays an important role in our daily lives by providing a source of renewable and clean energy. Solar energy can be harnessed through the use of solar panels, which convert sunlight into electricity. This can be used to power homes, businesses, and even vehicles. In addition, solar energy can also be used for heating and cooling, as well as for cooking and water heating. Solar energy is a sustainable and environmentally-friendly alternative to non-renewable sources of energy, which can have negative impacts on the environment and human health.

Chapter 15: Our Environment

Here are the Important Questions for Science Class 10 Chapter Our Environment:

What is an ecosystem? Give an example.
An ecosystem is a community of living and nonliving things interacting with each other in a specific environment. Example: A forest ecosystem, a coral reef ecosystem, a pond ecosystem.
Explain the concept of the food chain and food web.
A food chain is a linear sequence of organisms starting from the producer, followed by primary consumers and secondary consumers, ending with decomposers. A food web is a network of interconnected food chains in an ecosystem. It shows the flow of energy and nutrients from one organism to another. In a food web, several food chains are interconnected.
What are the different types of pollution?
The different types of pollution are air pollution, water pollution, soil pollution, noise pollution, and radioactive pollution. Air pollution is the presence of harmful substances in the air, water pollution is the contamination of water bodies, soil pollution is the presence of toxic substances in soil, noise pollution is excessive noise in the environment, and radioactive pollution is the presence of radioactive substances in the environment.
What is the difference between biodegradable and non-biodegradable waste?
Biodegradable waste can be broken down into natural substances by the action of microorganisms, whereas non-biodegradable waste cannot be broken down naturally. Biodegradable waste includes food waste, paper, and cardboard, while non-biodegradable waste includes plastic, metal, and glass.

Chapter 16: Sustainable Management of Natural Resources

What is meant by the term ‘natural resources’?
Natural resources are materials or substances that occur in nature and are useful to human beings. They can be categorized as renewable or non-renewable resources based on their availability and rate of replenishment.
What are the different methods of conservation of resources?
The different methods of conservation of resources are reducing the use of resources, adopting sustainable practices, recycling, reusing and finding alternative resources.
Explain the role of three R’s (Reduce, Reuse and Recycle) in the conservation of natural resources.
The three R’s – Reduce, Reuse and Recycle – play a vital role in the conservation of natural resources. By reducing the usage of resources, we decrease the amount of waste generated. By reusing products, we can reduce the amount of waste that goes to landfills, thus conserving resources. Recycling involves converting waste materials into new products, thereby reducing the need for new resources.
What is the importance of biodiversity in our lives?
Biodiversity is the variety of plant and animal life on Earth, including the ecosystems in which they live. It is important for human life in many ways, including providing food, medicine, and other resources, regulating the Earth’s climate, and helping to maintain the quality of the air, water, and soil. Biodiversity also has cultural and aesthetic value, and can serve as a source of inspiration and spiritual connection. Conserving biodiversity is therefore essential for the well-being of humans and the planet as a whole.

In conclusion, the above chapter-wise important questions for Science Class 10 can help students prepare better for the board exams. By answering these questions, students can have a clear understanding of the concepts taught in the curriculum and score well in the exams. It is important to note that these questions are not exhaustive, and students must practice a variety of questions to enhance their understanding of the subject.

Important Questions for Science Class 10 for CBSE