UP Board Class 10 Science Question Paper 2024 (Code 824 IK) Available :Download Solution PDF With Answer Key

When an object is positioned between the pole and the focus of a concave mirror, the image formed is erect, virtual, and larger than the object. This happens because the reflected rays diverge and seem to originate from a point behind the mirror, resulting in a magnified virtual image.
Quick Tip: Concave mirrors can form both real and virtual images depending on the position of the object.

A convex lens is employed to correct long-sightedness (hypermetropia). It aids in focusing light rays correctly onto the retina by converging the light before it enters the eye.
Quick Tip: Hypermetropia (far-sightedness) occurs when the eye cannot focus on nearby objects, requiring a convex lens for correction.

Given: \[ Object distance u = -0.2 \, m \quad (negative because the object is on the same side as the incident light). \] \[ Magnification M = 0.5. \] \[ The image is virtual, implying a positive magnification for a concave lens. \]

Step 1: Use the magnification formula

The magnification \( M \) for a lens is given by the formula: \[ M = \frac{v}{u} \]
Where: \[ v is the image distance, and u is the object distance. \]

Substituting the known values: \[ 0.5 = \frac{v}{-0.2} \]
Solving for \( v \): \[ v = 0.5 \times (-0.2) = -0.1 \, m \]
Thus, the image distance is \( v = -0.1 \, m \). The negative sign indicates that the image is virtual and formed on the same side as the object, which is characteristic of a concave lens.

Step 2: Use the lens formula to find the focal length

The lens formula is: \[ \frac{1}{f} = \frac{1}{v} - \frac{1}{u} \]
Where: \[ f is the focal length of the lens, v is the image distance, and u is the object distance. \]

Substitute the known values \( v = -0.1 \, m \) and \( u = -0.2 \, m \): \[ \frac{1}{f} = \frac{1}{-0.1} - \frac{1}{-0.2} \] \[ \frac{1}{f} = -10 + 5 = -5 \]
Therefore: \[ f = \frac{1}{-5} = -0.2 \, m \]
The negative focal length indicates that the lens is a concave lens.

Step 3: Conclusion

Thus, the lens is a concave lens with a focal length of \( 0.2 \, m \).

The correct answer is: \[ \boxed{(B) A concave lens of focal length 0.2 m.} \] Quick Tip: Concave lenses always form virtual, upright, and diminished images, whereas convex lenses can form both real and virtual images.

When white light passes through a prism, it undergoes dispersion, causing different colors to bend at varying angles. Violet light bends the most because it has the shortest wavelength among the visible light spectrum.
Quick Tip: Dispersion of light in a prism leads to the formation of a spectrum, with violet bending the most and red bending the least.

For resistors in parallel, the equivalent resistance formula is: \[ \frac{1}{R_{eq}} = \frac{1}{R_1} + \frac{1}{R_2} \]
which simplifies to: \[ R_{eq} = \frac{R_1 \times R_2}{R_1 + R_2} \] Quick Tip: In a parallel circuit, the total resistance is always less than the smallest individual resistance.

Tungsten is used as the filament in an electric bulb due to its high melting point (approximately 3400°C) and high resistivity, which enables it to produce bright light when heated.
Quick Tip: Tungsten filaments are chosen due to their ability to withstand high temperatures without melting.

An electric cell transforms chemical energy into electrical energy through a redox reaction occurring within the cell, where electrons flow from the negative electrode to the positive electrode.
Quick Tip: A battery operates by converting stored chemical energy into electrical energy used to power devices.

The given reaction represents the reduction of ferric chloride (\(FeCl_3\)) to ferrous chloride (\(FeCl_2\)) with sulfur dioxide (\(SO_2\)) acting as the reducing agent. In this reaction, sulfur dioxide reduces ferric chloride (\(FeCl_3\)) to ferrous chloride (\(FeCl_2\)), and itself gets oxidized to sulfuric acid (\(H_2SO_4\)). The reaction proceeds as: \[ 2 FeCl_3 + SO_2 + 2 H_2O \rightarrow 2 FeCl_2 + H_2SO_4 + 2 HCl \]
Thus, Y is \( SO_2 \).
Quick Tip: Sulfur dioxide (\(SO_2\)) is commonly used as a reducing agent in inorganic chemistry, especially in the reduction of metal chlorides.

An acidic salt is produced when a strong acid reacts with a weak base. Sodium bisulfate (\(NaHSO_4\)) is an acidic salt because it contains an ionizable hydrogen ion (\(H^+\)), which makes the solution acidic.

Quick Tip: Acidic salts form when a polybasic acid (like sulfuric acid) is only partially neutralized by a base.

Matte is a molten substance primarily made up of copper sulfide (Cu\(_2\)S) and iron sulfide (FeS), which is produced during the smelting of copper ores. It serves as an intermediate product in the process of extracting copper.

Quick Tip: Matte is further processed to extract pure copper by oxidation and reduction methods.

The reaction given is the conversion of acetic acid (CH\(_3\)COOH) into acetyl chloride (CH\(_3\)COCl) using phosphorus pentachloride (PCl\(_5\)). The complete reaction is: \[ CH_3COOH + PCl_5 \rightarrow CH_3COCl + POCl_3 + HCl \]
Acetyl chloride is an important reagent in organic synthesis.
Quick Tip: PCl\(_5\) is commonly used to convert carboxylic acids into acyl chlorides.

An amphoteric oxide is one that reacts with both acids and bases. Aluminum oxide (Al\(_2\)O\(_3\)) exhibits this behavior: \[ Al_2O_3 + 6HCl \rightarrow 2AlCl_3 + 3H_2O \] \[ Al_2O_3 + 2NaOH + 3H_2O \rightarrow 2Na[Al(OH)_4] \] Quick Tip: Al\(_2\)O\(_3\) is found in bauxite and is used in aluminum extraction.

Propane (C\(_3\)H\(_8\)) is a hydrocarbon that belongs to the alkane family. It is composed of three carbon atoms bonded to hydrogen in a single-bonded structure. Propane is commonly used as a fuel for heating and cooking. Quick Tip: Alkanes follow the general formula C\(_n\)H\(_{2n+2}\).

Hydra reproduces asexually through budding. A small outgrowth, known as a bud, develops on the parent's body. Over time, the bud grows and matures into a new individual before detaching from the parent. This mode of reproduction enables Hydra to reproduce efficiently.

Quick Tip: \textbf{Budding} is a common asexual reproduction method found in simple organisms like Hydra and yeast.

Pyruvate breakdown takes place in the mitochondria during aerobic respiration. Pyruvate is converted into Acetyl-CoA, which then enters the Krebs cycle, generating ATP, NADH, and FADH\(_2\). This process is crucial for energy production in cells.

Quick Tip: The \textbf{mitochondria} are known as the "powerhouse of the cell" because they generate ATP through aerobic respiration.

Kidneys are essential organs of the excretory system. They filter waste substances such as urea, excess salts, and water from the blood, which are then excreted as urine. This process is crucial for maintaining fluid balance in the body and eliminating toxins.

Quick Tip: The \textbf{excretory system} includes the kidneys, ureters, bladder, and urethra, which work together to remove waste from the body.

Gregor Mendel began his education at a school. He later joined a monastery, where he conducted his renowned genetic experiments on pea plants, resulting in the discovery of the basic laws of inheritance.

Quick Tip: Mendel is known as the \textbf{"Father of Genetics"} for his pioneering work on inheritance.

A loop or intrauterine device (IUD) is inserted into the uterus as a method of contraception to prevent pregnancy. It serves as a physical barrier to implantation and may also release hormones to help regulate fertility.

Quick Tip: IUDs are one of the most effective long-term reversible contraceptive methods.

The stamen is the male reproductive organ of a flower. It comprises the anther, which produces pollen grains, and the filament, which provides support to the anther. Pollen grains carry the male gametes required for fertilization.

Quick Tip: The \textbf{carpel (pistil)} represents the female reproductive organ in plants.

Environment-friendly practices involve reducing plastic usage, conserving energy, and minimizing carbon footprints. Using cloth bags helps cut down on plastic waste, turning off electrical devices conserves energy, and walking instead of driving reduces air pollution.

Quick Tip: \textbf{Reduce, Reuse, and Recycle} are the three essential principles of environmental conservation.

Let the object distance be \( u \) and the image distance be \( v \). Given that the magnification \( m \) is -5 for a real and inverted image, we use: \[ m = \frac{-v}{u} \] \[ v = -5u \]
Using the mirror formula: \[ \frac{1}{f} = \frac{1}{u} + \frac{1}{v} \]
Substituting \( f = -10 \) cm and \( v = -5u \): \[ \frac{1}{-10} = \frac{1}{u} + \frac{1}{-5u} \]
Solving, we get \( u = -12 \) cm and \( v = -60 \) cm.
Quick Tip: A real and inverted image means the image distance is negative.

Using the lens formula: \[ \frac{1}{f} = \frac{1}{v} - \frac{1}{u} \]
Given \( f = 50 \) cm and \( u = -25 \) cm: \[ \frac{1}{50} = \frac{1}{v} - \frac{1}{-25} \] \[ \frac{1}{v} = \frac{1}{50} - \frac{1}{25} = \frac{1}{50} - \frac{2}{50} = \frac{-1}{50} \] \[ v = -50 cm \]
The image is formed at -50 cm, meaning it is virtual and on the same side as the object.

Magnification is given by: \[ m = \frac{v}{u} = \frac{-50}{-25} = 2 \]
Thus, the image is magnified and erect.
Quick Tip: A negative image distance in convex lenses indicates a virtual image.

In a series circuit, the same current flows through all resistors. Using Ohm’s law: \[ V = IR \]
Total resistance: \[ R_{total} = 2 + 3 + 5 = 10Ω \]
Total current: \[ I = \frac{V}{R_{total}} = \frac{30}{10} = 3A \]
Voltage drop across each resistor: \[ V_1 = IR_1 = (3)(2) = 6V \] \[ V_2 = IR_2 = (3)(3) = 9V \] \[ V_3 = IR_3 = (3)(5) = 15V \]
Thus, the potential differences across 2Ω, 3Ω, and 5Ω resistors are 6V, 9V, and 15V, respectively.
Quick Tip: In a series circuit, the sum of individual voltage drops equals the total supplied voltage.

The domestic electrical distribution circuit consists of three main types of wires:


- Live Wire: This wire carries the current from the supply to the electrical appliance. It is typically red or brown in color.

- Neutral Wire: It completes the circuit by carrying the current back to the power source. It is usually black or blue in color.

- Earthing Wire: This wire provides safety by preventing electric shocks. It carries leakage current to the ground and is generally green or yellow-green in color.
Quick Tip: The earthing wire is crucial for preventing electric shocks by directing excess current safely into the ground.

- Fleming’s Left Hand Rule: This rule is used to determine the direction of force experienced by a current-carrying conductor in a magnetic field. It states that if the thumb, forefinger, and middle finger of the left hand are stretched perpendicular to each other:

- Forefinger represents the direction of the magnetic field.

- Middle finger represents the direction of current.

- Thumb represents the direction of force (motion).

- Right Hand Thumb Rule: This rule is used to determine the direction of the magnetic field around a current-carrying conductor. If the thumb of the right hand points in the direction of current, then the curled fingers represent the direction of the magnetic field. Quick Tip: Fleming’s Left Hand Rule is used in motors, while the Right Hand Thumb Rule helps in understanding electromagnetism and solenoid fields.

(i) Lead nitrate is heated:
\[ 2 \, Pb(NO_3)_2 \xrightarrow{heat} 2 \, PbO + 4 \, NO_2 + O_2 \]

(ii) Ethanoic acid reacts with Sodium carbonate:
\[ CH_3COOH + Na_2CO_3 \rightarrow 2 \, CH_3COONa + CO_2 + H_2O \]

(iii) Reaction of Zinc with Silver nitrate:
\[ Zn + 2 \, AgNO_3 \rightarrow Zn(NO_3)_2 + 2 \, Ag \]

(iv) Reaction of Sodium sulphate solution with Barium chloride solution:
\[ Na_2SO_4 + BaCl_2 \rightarrow BaSO_4 + 2 \, NaCl \]
Quick Tip: Balanced chemical equations are essential for understanding the stoichiometry of reactions.

(i) Homologous series: A homologous series is a series of organic compounds with similar chemical properties and a gradual change in physical properties, where each member differs by a -CH₂ group. Examples include alkanes, alkenes, and alkynes.


(ii) Versatile nature of Carbon: Carbon is versatile because it can form long chains, rings, and networks, which are the basis for organic chemistry. Carbon atoms can bond with other elements to form a variety of organic compounds, including hydrocarbons, sugars, and proteins.
Quick Tip: Carbon’s versatility makes it the backbone of organic life.

(i) CH₃COOH is Ethanoic acid.

(ii) CH₃CH₂CH₂Cl is 1-chloropropane.

(iii) CH ≡ CH is Ethyne.
Quick Tip: Always remember to follow IUPAC rules for naming compounds based on structure.

(i) Exothermic reaction: These are reactions in which heat is released to the surroundings. The energy required to break bonds is less than the energy released when new bonds are formed. Examples include combustion and respiration.

(ii) Endothermic reaction: These are reactions in which heat is absorbed from the surroundings. The energy required to break bonds is more than the energy released when new bonds are formed. An example is photosynthesis.
Quick Tip: In exothermic reactions, heat is released, and in endothermic reactions, heat is absorbed.

The pH value is a measure of the hydrogen ion concentration in a solution. It is calculated as the negative logarithm of the hydrogen ion concentration, i.e., \(pH = -\log[H^+]\). The higher the concentration of hydrogen ions, the lower the pH, indicating an acidic solution. Conversely, a lower concentration of hydrogen ions results in a higher pH, indicating a basic solution.

For example, a pH of 7 indicates neutrality (pure water), while values below 7 indicate acidity and above 7 indicate alkalinity.
Quick Tip: A decrease in pH indicates an increase in hydrogen ion concentration, and an increase in pH indicates a decrease in hydrogen ion concentration.

(i) Minerals: A mineral is a naturally occurring inorganic substance with a definite chemical composition and crystal structure. Minerals are the raw materials from which metals can be extracted. For example, \(Haematite (Fe_2O_3)\) is a mineral.

(ii) Ores: An ore is a naturally occurring mineral from which metals can be extracted profitably. It is usually a mixture of a metal compound with other elements. For example, \(Bauxite (Al_2O_3)\) is an ore of aluminum.
Quick Tip: All ores are minerals, but not all minerals are ores.

Saliva contains amylase, an enzyme that initiates the process of breaking down starch into sugar in the mouth. It also acts as a lubricant, facilitating easier swallowing of food. Furthermore, saliva plays a role in maintaining oral hygiene by neutralizing acids and removing food particles.

Quick Tip: Saliva not only aids in digestion but also plays a crucial role in oral health by protecting teeth and gums.

The ozone layer absorbs and shields life on Earth from harmful ultraviolet (UV) radiation emitted by the Sun. Without the ozone layer, this radiation could lead to skin cancer, cataracts, and harm to both plant and animal life. The ozone layer is crucial for preserving the Earth's ecosystem.
Quick Tip: The ozone layer is like Earth's sunscreen, shielding us from the Sun’s harmful rays.

\begin{tabular{|l|l|
\hline
Self-pollination & Cross-pollination

\hline
Pollen from the same flower or plant fertilizes the stigma. & Pollen from one plant fertilizes the stigma of another plant of the same species.

\hline
No involvement of other plants. & Involves different plants.

\hline
No external agents; pollen remains within the same plant. & Often involves external agents like wind, water, or animals.

\hline
Results in less genetic variation. & Promotes genetic diversity, leading to more adaptability.

\hline
Examples: Pea plants, wheat. & Examples: Apple, cherry, and many flowers.

\hline
\end{tabular Quick Tip: Cross-pollination promotes genetic diversity, which is beneficial for the adaptability of species.

Two permanent methods of family planning are:

Sterilization: A surgical procedure that permanently prevents pregnancy. In men, this is called vasectomy, and in women, it is called tubectomy.

Contraceptive Implants: A small rod inserted under the skin that releases hormones to prevent pregnancy for several years.
Quick Tip: Permanent methods of family planning are effective in ensuring long-term reproductive health management.

Auxins: Promote stem elongation, root growth, and cell differentiation. They play a key role in plant responses to light (phototropism) and gravity (gravitropism).

Gibberellins: Stimulate growth and increase fruit size. They also promote seed germination.
Quick Tip: Plant hormones help regulate growth, development, and responses to environmental stimuli.

Stomata are small pores found on the surface of leaves and stems that facilitate gas exchange. They control the intake of carbon dioxide and the release of oxygen and water vapor. Stomata are essential for both photosynthesis and transpiration.

Quick Tip: Stomata not only control gas exchange but also help in regulating the water balance within the plant.

The nephron is the functional unit of the kidney responsible for filtration, reabsorption, and secretion. Each kidney contains about 1 million nephrons. It consists of two main parts: the renal corpuscle and the renal tubule.



1. Renal Corpuscle:
- Glomerulus: A network of capillaries where blood filtration occurs.
- Bowman’s Capsule: Surrounds the glomerulus and collects the filtered fluid.



2. Renal Tubule:
- Proximal Convoluted Tubule (PCT): Reabsorbs water, glucose, and ions like sodium and potassium.
- Loop of Henle: Concentrates urine by reabsorbing water (descending) and sodium chloride (ascending).
- Distal Convoluted Tubule (DCT): Further reabsorption of ions and regulation of acid-base balance.
- Collecting Duct: Final water reabsorption influenced by ADH, and secretion of excess ions.



Function of the Nephron:
1. Filtration: Blood is filtered in the glomerulus, and waste products and small molecules pass into the Bowman’s capsule.
2. Reabsorption: Essential substances like glucose, water, and ions are reabsorbed back into the bloodstream.
3. Secretion: Additional waste products (e.g., urea, excess ions) are secreted into the renal tubule for elimination.



The nephron plays a key role in regulating the body’s fluid, electrolyte balance, and eliminating waste via urine formation. Quick Tip: Nephrons regulate water, electrolytes, and waste removal, maintaining homeostasis.

Mendel's work with pea plants led to the formulation of the basic laws of inheritance. His principles of dominance, segregation, and independent assortment provided an explanation for how traits are inherited from parents to offspring. These groundbreaking experiments formed the foundation of modern genetics, enhancing our understanding of how genes and alleles influence traits in organisms.
.
Quick Tip: Mendel’s experiments were the starting point for genetic studies, providing a framework for understanding heredity.