HP Board Class 10 Science and Technology 2026 Question Paper with Solution PDF : Available Here

Step 1: Using the power formula.


The power of an electric device is given by the relation:

\[ P = \frac{V^2}{R} \]

where \(P\) is power, \(V\) is voltage, and \(R\) is resistance.


Step 2: Finding the resistance of the bulb.


Given rating of the bulb: \(V = 220\,V\) and \(P = 100\,W\).

\[ R = \frac{V^2}{P} \]
\[ R = \frac{220^2}{100} \]
\[ R = \frac{48400}{100} = 484 \,\Omega \]

Step 3: Calculating power at 110 V.


Now the bulb is operated at \(V = 110\,V\).

\[ P = \frac{V^2}{R} \]
\[ P = \frac{110^2}{484} \]
\[ P = \frac{12100}{484} = 25\,W \]

Step 4: Conclusion.


Therefore, when the bulb operates at 110 V, the power consumed becomes 25 W.


Final Answer: 25 W. Quick Tip: For the same device, resistance remains constant. Since power \(P \propto V^2\), if voltage becomes half, power becomes one-fourth.

Step 1: Understanding neurons.


Neurons are specialized cells that transmit nerve impulses in the nervous system. They communicate with each other through a junction between two nerve cells.


Step 2: Definition of synapse.


The small gap between the axon terminal of one neuron and the dendrite of another neuron is called a synapse. Chemical substances called neurotransmitters carry signals across this gap.


Step 3: Comparison with other options.



(A) Dendrite: A part of the neuron that receives signals.

(B) Synapse: Correct. It is the gap between two neurons.

(C) Axon: A long fiber that carries impulses away from the cell body.

(D) Impulse: The electrical signal transmitted through neurons.



Step 4: Conclusion.


Thus, the gap between two neurons is called a synapse.


Final Answer: Synapse. Quick Tip: Signals travel from one neuron to another through a tiny junction called a synapse using neurotransmitters.

Step 1: Understanding the structure of a flower.


A flower is the reproductive organ of a plant. The male reproductive part is called the stamen, which consists of two parts: filament and anther.


Step 2: Function of the anther.


The anther is responsible for producing pollen grains. These pollen grains contain the male gametes required for fertilization in flowering plants.


Step 3: Comparison with other options.



(A) Sepals: Protective leaf-like structures of the flower bud.

(B) Ovules: Located inside the ovary of the pistil.

(C) Pistil: The female reproductive part of the flower.

(D) Pollen grains: Correct. These are produced inside the anther.



Step 4: Conclusion.


Hence, the anther contains pollen grains.


Final Answer: Pollen grains. Quick Tip: The stamen is the male reproductive part of a flower and its anther produces pollen grains containing male gametes.

Step 1: Understanding the reaction.


Aluminium reacts with chlorine gas to form aluminium chloride. Aluminium has a valency of 3, while chlorine has a valency of 1. Therefore, aluminium combines with three chlorine atoms to form aluminium chloride (AlCl\(_3\)).


Step 2: Writing the chemical equation.


The basic chemical reaction can be written as:

Al + Cl\(_2\) \(\rightarrow\) AlCl\(_3\)


However, this equation is not balanced because the number of aluminium and chlorine atoms on both sides must be equal.


Step 3: Balancing the equation.


To balance the equation, we take two aluminium atoms and three chlorine molecules so that both sides have equal numbers of atoms. The balanced chemical equation becomes:


2Al + 3Cl\(_2\) \(\rightarrow\) 2AlCl\(_3\)


Step 4: Conclusion.


Thus, the correct chemical equation for the formation of aluminium chloride from aluminium and chlorine is 2Al + 3Cl\(_2\) \(\rightarrow\) 2AlCl\(_3\).


Final Answer: 2Al + 3Cl\(_2\) \(\rightarrow\) 2AlCl\(_3\). Quick Tip: When writing chemical equations, always ensure that the number of atoms of each element is equal on both sides of the equation to satisfy the law of conservation of mass.

Step 1: Understanding amoeba.


Amoeba is a unicellular organism that feeds on microorganisms and organic particles. It captures food using extensions of its cytoplasm called pseudopodia.


Step 2: Formation of food vacuole.


After engulfing food, the amoeba encloses it inside a membrane-bound structure called a food vacuole. Digestive enzymes act inside this vacuole and break down the food into simpler substances.


Step 3: Comparison with other options.



(A) Food vacuole: Correct. Digestion occurs inside the food vacuole.

(B) Mitochondria: Responsible for energy production.

(C) Pseudopodia: Used for movement and capturing food.

(D) Chloroplast: Found in plants for photosynthesis.



Step 4: Conclusion.


Hence, digestion in amoeba occurs inside the food vacuole.


Final Answer: Food vacuole. Quick Tip: Amoeba captures food by pseudopodia but digestion takes place inside the food vacuole.

Step 1: Understanding lactic acid.


Lactic acid is an organic acid produced during the fermentation of lactose (milk sugar) by bacteria known as Lactobacillus. This process commonly occurs in dairy products.


Step 2: Formation in curd.


When milk is converted into curd, bacteria ferment lactose and produce lactic acid. The presence of lactic acid causes milk to coagulate and gives curd its characteristic sour taste.


Step 3: Comparison with options.



(A) Orange: Contains citric acid.

(B) Tea: Does not contain lactic acid.

(C) Curd: Correct. Lactic acid is produced during fermentation of milk to form curd.

(D) Vinegar: Contains acetic acid.



Step 4: Conclusion.


Therefore, lactic acid is present in curd.


Final Answer: Curd. Quick Tip: Curd is formed when Lactobacillus bacteria convert lactose in milk into lactic acid.

Step 1: Understanding food preservation.


Food preservation involves methods that prevent spoilage caused by microorganisms such as bacteria and fungi. One common technique is removing oxygen from food packaging to slow down microbial growth and oxidation.


Step 2: Role of nitrogen in food preservation.


Nitrogen gas is an inert and non-reactive gas. It is used in food packaging to replace oxygen in packets of chips, snacks, and other packaged foods. This prevents oxidation and helps maintain freshness.


Step 3: Comparison with options.



(A) Carbon: Not used directly for preserving packaged food.

(B) Phosphorus: Highly reactive and not suitable for food preservation.

(C) Sulphur: Sometimes used in compounds for preservation but not commonly as elemental sulphur.

(D) Nitrogen: Correct. Nitrogen gas is widely used in food packaging to preserve food.



Step 4: Conclusion.


Thus, nitrogen is the non-metal commonly used to preserve food materials.


Final Answer: Nitrogen. Quick Tip: Nitrogen gas is used in food packets to prevent oxidation and maintain freshness because it is inert and does not react with food.

Step 1: Understanding the naming of carbon compounds.


Organic compounds that contain only carbon and hydrogen are called hydrocarbons. These compounds are named according to the number of carbon atoms present in their molecular structure. The International Union of Pure and Applied Chemistry (IUPAC) provides standard prefixes for naming these compounds.


Step 2: Prefixes used for carbon atoms.


The prefixes used for different numbers of carbon atoms are:



1 Carbon atom → Methane
2 Carbon atoms → Ethane
3 Carbon atoms → Propane
4 Carbon atoms → Butane


Step 3: Applying the concept.


Since the compound mentioned in the question contains two carbon atoms, the correct prefix is Eth. Therefore, the hydrocarbon containing two carbon atoms is called Ethane.


Step 4: Conclusion.


Thus, a carbon compound containing two carbon atoms is named Ethane.



Final Answer: Ethane. Quick Tip: Remember the basic hydrocarbon prefixes: Meth (1 carbon), Eth (2 carbons), Prop (3 carbons), But (4 carbons). These prefixes help in naming organic compounds.

Step 1: Understanding reflection of light.


Reflection of light occurs when light rays strike a surface and bounce back into the same medium. The behavior of reflected light is explained by the laws of reflection.


Step 2: Laws of reflection.


There are two fundamental laws of reflection:



The incident ray, the reflected ray, and the normal at the point of incidence all lie in the same plane.
The angle of incidence is always equal to the angle of reflection.


Step 3: Evaluating the options.



(A) The angle of incidence and reflection are equal: Correct. This is the fundamental law of reflection.
(B) The reflected light is less bright: Incorrect. Brightness depends on the surface and absorption, not a law of reflection.
(C) Sum of angles always greater than \(90^\circ\): Incorrect. There is no such rule in reflection.
(D) Rays diverge at unequal angles: Incorrect. The relationship between angles is fixed by the law of reflection.


Step 4: Conclusion.


Therefore, according to the laws of reflection, the angle of incidence is equal to the angle of reflection.



Final Answer: The angle of incidence and reflection are equal. Quick Tip: Always remember the key law of reflection: \textbf{Angle of incidence = Angle of reflection}. This principle is used in mirrors, periscopes, and optical instruments.

Step 1: Formation of urine.

Urine is formed in the kidneys as part of the excretory process. It helps remove waste products such as urea, excess salts and extra water from the blood.


Step 2: Purpose of urine formation.

The main purpose of making urine is to eliminate harmful metabolic wastes from the body and maintain the balance of water and salts in the body.


Step 3: Organ that stores urine.

The urinary bladder stores urine temporarily until it is released from the body through the urethra.


Step 4: Conclusion.

Thus, urine formation helps remove wastes from the body, and the urinary bladder stores and releases urine.
Quick Tip: The kidneys produce urine, the ureters carry it, the urinary bladder stores it and the urethra releases it from the body.

Step 1: Understanding the structure of the human eye.


The human eye works like a camera. Light from an object enters the eye through the cornea and passes through different parts of the eye before forming an image.


Step 2: Path of light in the eye.


The light travels through the following parts:



Cornea – allows light to enter the eye
Pupil – controls the amount of light entering the eye
Lens – focuses the light rays
Retina – the screen where the image is formed


Step 3: Formation of image.


The eye lens focuses the incoming light rays onto the retina. The retina contains light-sensitive cells called rods and cones that detect the image and convert it into electrical signals. These signals are then transmitted to the brain through the optic nerve.


Step 4: Conclusion.


Therefore, the image of an object in the human eye is formed on the retina.



Final Answer: Retina. Quick Tip: The retina acts like the screen of a camera where the real and inverted image of an object is formed before being interpreted by the brain.

Step 1: Formula for refractive index.

The refractive index of a medium is given by:
\[ n=\frac{c}{v} \]

where \( n \) is refractive index, \( c \) is speed of light in vacuum, and \( v \) is speed of light in the medium.


Step 2: Substitute given values.
\[ 1.50=\frac{3\times10^8}{v} \]


Step 3: Calculate the speed of light in glass.
\[ v=\frac{3\times10^8}{1.50} \]
\[ v=2\times10^8 \, m s^{-1} \]


Step 4: Conclusion.

Thus, the speed of light in glass is \(2\times10^8\) m s\(^{-1}\).
Quick Tip: Refractive index tells how much the speed of light decreases when it enters a medium from vacuum.

Step 1: Property of convex mirror.

A convex mirror always forms a virtual, erect and diminished image of objects placed in front of it.


Step 2: Wide field of view.

Convex mirrors provide a wider field of view compared to plane mirrors. This allows the driver to see a larger area of the road behind the vehicle.


Step 3: Application in vehicles.

Because of the wider field of view and upright images, convex mirrors help drivers observe vehicles coming from behind more easily and safely.


Step 4: Conclusion.

Therefore, convex mirrors are preferred as rear view mirrors in vehicles because they provide a wide field of view and form erect images of the traffic behind.
Quick Tip: Convex mirrors are called diverging mirrors and are used as rear-view mirrors because they show a larger area of traffic behind the vehicle.

Step 1: Near point of the eye.

For a normal human eye, the minimum distance at which objects can be seen clearly is called the near point, which is approximately 25 cm.


Step 2: Limitation of eye lens.

When an object is placed closer than 25 cm, the eye lens cannot become sufficiently thick to focus the image on the retina.


Step 3: Effect on image formation.

As a result, the image formed on the retina becomes blurred and the object cannot be seen clearly.


Step 4: Conclusion.

Therefore, objects placed closer than 25 cm cannot be seen clearly by a normal eye because the eye lens cannot adjust its focal length enough to focus the image on the retina.
Quick Tip: The near point of a normal human eye is 25 cm, which is the closest distance at which objects can be seen clearly.

Step 1: Meaning of diffusion.

Diffusion is the movement of substances from a region of higher concentration to a region of lower concentration.


Step 2: Limitation in multicellular organisms.

In multicellular organisms like humans, the body is large and consists of many cells located far from the external environment.


Step 3: Oxygen requirement of cells.

Cells require a large and continuous supply of oxygen for respiration. Diffusion alone is too slow to transport oxygen to all the cells of the body.


Step 4: Conclusion.

Therefore, diffusion is insufficient to meet the oxygen requirements of multicellular organisms, and specialised respiratory and circulatory systems are needed to transport oxygen efficiently.
Quick Tip: Large organisms require specialised transport systems like lungs and blood circulation to deliver oxygen to all body cells.

Step 1: Movement in sensitive plant.

The leaves of the sensitive plant (Mimosa pudica) fold when touched. This type of movement is called nastic movement. It occurs due to changes in turgor pressure in the cells and does not depend on the direction of the stimulus.


Step 2: Movement of shoot towards light.

The movement of a plant shoot towards light is known as phototropism. It is a growth movement that occurs in response to the direction of light.


Step 3: Key difference.

The movement of leaves in a sensitive plant is a rapid, non-growth movement caused by touch, whereas the movement of the shoot towards light is a slow growth movement directed by the stimulus of light.


Step 4: Conclusion.

Thus, sensitive plant movement is nastic and non-directional, while shoot movement towards light is a directional growth movement called phototropism.
Quick Tip: Nastic movements are independent of stimulus direction, while tropic movements depend on the direction of the stimulus.

Step 1: Formation of oxide layer.

When magnesium ribbon is exposed to air, it reacts slowly with oxygen present in the air and forms a thin layer of magnesium oxide on its surface.


Step 2: Effect of oxide layer.

This magnesium oxide layer prevents the magnesium metal from burning easily because it blocks direct contact between the magnesium metal and oxygen in the air.


Step 3: Cleaning the ribbon.

Therefore, the magnesium ribbon is cleaned with sandpaper before burning to remove the oxide layer present on its surface.


Step 4: Conclusion.

After removing the oxide layer, the magnesium metal can react directly with oxygen and burn brightly producing magnesium oxide.
Quick Tip: Magnesium ribbon is cleaned to remove the magnesium oxide layer that forms due to exposure to air.

Step 1: Nature of dilution reaction.

The process of diluting a concentrated acid with water is highly exothermic, which means it releases a large amount of heat.


Step 2: Adding water to acid.

If water is added directly to concentrated acid, the heat generated may cause the mixture to splash out of the container, which can lead to burns or accidents.


Step 3: Adding acid to water.

When acid is slowly added to water with continuous stirring, the heat produced is absorbed by the large amount of water, making the process safer.


Step 4: Conclusion.

Therefore, acid should always be added to water slowly and carefully to prevent splashing and ensure safe dilution.
Quick Tip: Remember the rule: Always add acid to water, never water to acid.

Step 1: Requirement in welding.

Welding requires a very high temperature flame to melt and join metals effectively.


Step 2: Ethyne with oxygen.

When ethyne burns in pure oxygen, it produces a very high temperature flame (about 3000°C), which is suitable for welding metals.


Step 3: Ethyne with air.

Air contains only about 21% oxygen and a large amount of nitrogen, so the combustion of ethyne in air produces a lower temperature flame.


Step 4: Conclusion.

Therefore, a mixture of ethyne and air is not used for welding because it does not produce a flame hot enough for welding processes.
Quick Tip: Oxy-acetylene flame is used in welding because it produces extremely high temperatures required to melt metals.

Step 1: Hormone present in regions of rapid cell division.

The hormone found in areas of rapid cell division in plants is Cytokinin. Cytokinins promote cell division (cytokinesis) and are mainly present in actively growing tissues such as root tips, shoot tips and developing fruits.


Step 2: Hormone that inhibits plant growth.

The hormone that inhibits plant growth is Abscisic Acid (ABA). It acts as a growth inhibitor and helps plants respond to stress conditions such as drought. It also induces dormancy in seeds and buds.


Step 3: Conclusion.

Thus, Cytokinin is present in areas of rapid cell division in plants, while Abscisic Acid (ABA) acts as a hormone that inhibits plant growth.
Quick Tip: Cytokinins promote cell division in plants, whereas Abscisic Acid (ABA) acts as a growth inhibitor and stress hormone.