Module 1 - MCQ Test, Class 10, Science - Class 10 MCQ

Explanation:Breathing is rhythmic. It is the intake of oxygen and expulsion of carbon dioxide. Respiration is the production of energy in the body, which includes breathing, mastication etc. Through this process, oxygen is inhaled. This inhaled oxygen is used to burn/oxidize/break down the food (glucose). This reaction produces energy which is used to carry out various activities going in our body. Our body needs continuous supply of energy to carry out these activities.  So, respiration is a continuous process which makes us able to meet energy demands of our body. If respiration comes to halt the person will die.

Explanation:Nitrogen is a component of amino acids and urea. Amino acids are the building blocks of all proteins. So, N is essential for the formation of protein.

• Chlorophyll: Chlorophyll is a green pigment found in plants and algae. It is essential for photosynthesis, the process by which plants convert light energy into chemical energy.



• Xanthophylls: Xanthophylls are yellow pigments that are also found in plants. They play a role in light harvesting and photoprotection in photosynthetic organisms.



• Carotene: Carotene is an orange pigment found in fruits and vegetables. It is a precursor to vitamin A and acts as an antioxidant in the body.

• Pigments are responsible for the coloration of plants, fruits, and vegetables.



• They play a crucial role in photosynthesis by capturing light energy and converting it into chemical energy.



• Pigments also act as antioxidants, protecting cells from damage caused by free radicals.



• They are essential for the health and growth of plants and play a role in human nutrition as well.

In conclusion, chlorophyll, xanthophylls, and carotene are important pigments that serve various functions in plants and organisms. They are essential for processes like photosynthesis and provide color and health benefits to plants and humans.

• Carbon dioxide: Carbon dioxide is one of the raw materials required for photosynthesis. It is absorbed by plants from the atmosphere through small openings in their leaves called stomata.


• Oxygen: Although oxygen is produced during photosynthesis as a byproduct, it is not a raw material required for the process itself.


• Water: Water is another essential raw material needed for photosynthesis. Plants absorb water through their roots and transport it to the leaves where it is used in the process.


• Chlorophyll: Chlorophyll is a pigment found in the chloroplasts of plant cells. While it is essential for capturing light energy, it is not considered a raw material for photosynthesis.

Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy, usually from the sun, into chemical energy stored in glucose. This process requires several raw materials, including carbon dioxide, water, and light energy. These raw materials are used by plants to produce glucose and oxygen as byproducts. Carbon dioxide is absorbed from the atmosphere, water is absorbed from the soil, and light energy is captured by chlorophyll in the chloroplasts of plant cells. Together, these raw materials are essential for the production of glucose, which serves as a source of energy for the plant and other organisms in the ecosystem.

Explanation:Unlike plants, which use carbon dioxide and light as sources of carbon and energy, respectively, fungi meet these two requirements by assimilating preformed organic matter; carbohydrates are generally the preferred carbon source. As fungi grow on land and obtain their nutrients from dead organic matter, Thatswhy, Mode of nutrition in fungi is saprotrophic.

Explanation:Wind velocity doesn't affect the photosynthesis. Unlike light intensity, CO2 concentration, and temperature which are the major factors influencing the rate of photosynthesis, the wind has no effect on the reactions and the rate of reactions going in the chloroplast of the leaves of the plant.

• Gizzard: The gizzard is a part of the digestive system found in some animals that helps with the mechanical breakdown of food.


• Function: The gizzard is responsible for grinding food into smaller particles that can be easily digested.


• Grasshopper: Grasshoppers are known to have a gizzard in their digestive system.


• Food: Grasshoppers are herbivorous insects that feed on plant material, which needs to be broken down efficiently for digestion.


• Importance: The gizzard in grasshoppers plays a crucial role in helping them digest their food effectively.

Therefore, the correct answer is B: grasshopper.

Explanation:The plastid is a major double-membrane organelle found in the meristematic tissues especially inside parenchyma cells of the plants or leaves, and the Parenchyma is present inside the central leaf or mesophyll.

• Plasma: Plasma is the component of blood that transports carbon dioxide and nitrogenous wastes in dissolved form.

• Transportation: Plasma carries carbon dioxide from body tissues to the lungs for exhalation and transports nitrogenous wastes to the kidneys for excretion.


• Dissolved Form: These waste products are carried in dissolved form in the liquid part of the blood, which is plasma.


• Composition: Plasma is primarily composed of water, electrolytes, proteins, and waste products, making it an essential medium for transporting these substances.

• Regulation: Plasma plays a crucial role in maintaining the body's acid-base balance by transporting and eliminating waste products efficiently.


• Excretion: By transporting carbon dioxide and nitrogenous wastes, plasma helps in the excretory functions of the body, aiding in the removal of harmful substances.

Explanation:Saliva contains the enzyme amylase, also called ptyalin, which is capable of breaking down starch into simpler sugars such as maltose and dextrin that can be further broken down in the small intestine. Only about 30% starch digestion takes place in the mouth cavity.

Explanation:Metals are electropositive in nature and are therefore, good conductors of electricity. Quartz is a chemical compound consisting of one part silicon and two parts oxygen (SiO2). It is the most abundant mineral found in Earth's surface. Its unique properties make it one of the most useful natural substances. It has electrical properties and heat resistance that make it valuable in electronic products. Mica has superior electrical properties as an insulator. Rubber is also an insulator.

Explanation:Electrical resistivity (also known as resistivity) is an intrinsic property of a material that quantifies how strongly a given material opposes the flow of electric current. Resistivity of a material varies with temperature. Resistivity of a conductor increases with increase in temperature. When a wire is stretched, its material remains the same and hence, the resistivity remains the same.

Explanation:The path of motion of free electrons in a metal is zig-zag. The normal motion of “free” electrons in a conductor is random, with no particular direction or speed.

A Rheostat is an electrical instrument used to control current in a circuit by varying the resistance. The resistance can be decreased or increased with the help of a rheostat.

Explanation:The two ebonite rods rubbed on fur repel each other because the electrical properties of the two ebonite rods are similar to each other. Both the rods acquire like charges when rubbed on fur. Ebonite is a very hard rubber obtained by vulcanizing natural rubber for prolonged periods. The rods gain electrons when rubbed on fur and acquire negative charge.

Explanation:Many conductors do not obey ohm's law. They are known as non-ohmic conductors. For such conductors, the graph between potential difference and current is not a straight line passing through the origin. Vacuum tubes, semiconductor diodes, transistors, liquid electrolytes, thermistors, etc are examples of such conductors.

Explanation:Electrons are not consumed in an electrical circuit. Energy provided to an electric circuit moves electrons through gadgets like electric iron, bulbs, etc.

Explanation:As a convention, the direction of flow of positive charge was taken to be the direction of electric current. The direction of flow of electrons is opposite to the direction of conventional current.

Explanation:Electric current is the rate of flow of electric charges. Movement of free electrons inside a metallic wire constitutes a flow of charge. Conventionally, in an electric circuit, the direction of electric current is taken as opposite to the direction of flow of electrons.

Explanation: It is placed on the extreme left of the periodic table where the metallic character of elements is maximum.

Explanation:CuSO₄ dissolves in water to give blue colour

Explanation:Mg combines with O₂ to form MgO so oxidized 

Explanation:Metals react with acids to form metal salt and hydrogen gas 

• Reactants: Diluted HCl and Zinc Metal


• Reaction: Zinc + Hydrochloric Acid → Zinc Chloride + Hydrogen Gas


• Gas Evolved: Hydrogen Gas

• Burning Splinter Test: When a burning splinter is brought near the gas evolved, hydrogen gas will ignite with a "pop" sound.


• Characteristics of Hydrogen Gas: Hydrogen gas is highly flammable and supports combustion. When it comes in contact with a burning splinter, it produces a distinctive sound indicating its presence.


• Confirmation: The "pop" sound produced by hydrogen gas confirms its presence in the reaction mixture, helping to identify the gas evolved accurately.

• Correct Answer: Option B - A burning splinter is required to identify the gas evolved when diluted HCl reacts with zinc metal.


• Importance: The burning splinter test is a simple and effective method to confirm the presence of hydrogen gas in the reaction, providing a clear indication of the gas evolved.

Explanation:One element which is higher in the reactivity series displaces the one which is lower from its compound is called displacement reaction 

Explanation:Fe is higher in the reactivity series than Cu so it displaces Cu from its compound 

Explanation: Reaction will take place between Fe and CuSO₄ and Fe will displace Cu from CuSO₄

• All of these: The decolourization of a blue solution of copper sulphate can be achieved by adding any of the following metals: Zn, Fe, and Al.


• Zn: Zinc has a higher reactivity than copper and can displace copper from its solution, leading to the decolourization of the blue copper sulphate solution.


• Fe: Iron also has a higher reactivity than copper and can displace copper from its solution, causing the blue copper sulphate solution to lose its color.


• Al: Aluminum, being more reactive than copper, can also displace copper from its solution, resulting in the decolourization of the blue copper sulphate solution.

Therefore, all of these metals (Zn, Fe, and Al) can decolourize a blue solution of copper sulphate by displacing copper from the solution due to their higher reactivity.

Explanation:Double displacement reactionit is so because it is a chemical reaction involving exchange of bonds between two reacting species 

• Iron articles should be covered with plastic: This is not an effective method of preventing rusting as plastic does not provide a barrier against moisture, which is a key factor in the rusting process.


• Galvanised iron pipes are used for water supply: Galvanised iron pipes have a protective zinc coating that helps prevent rusting by acting as a sacrificial anode.


• The iron articles should be painted: Painting iron articles creates a barrier that prevents moisture and oxygen from coming into contact with the iron surface, thus preventing rusting.


• The machine parts should be oiled or greased: Oiling or greasing machine parts creates a protective layer that prevents moisture from reaching the metal surface, thereby reducing the risk of rusting.