HBSE 10th Science Solved Sample Paper 2023

 HBSE 10th Science Solved Sample Paper 2023 

 

 

Q1. Unit of electric power is :   

      (A) Ohm 

      (B) Watt 

      (C) Ohm-meter 

      (D) Volt 

      

Q2. Human eye forms the image of an object at its :  

      (A) Retina  

      (B) Pupil  

      (C) iris     

      (D) Cornea 

 

Q3. Which of the following is not a Bio-mass energy source?  

      (A) Wood  

      (B) Gobar gas   

      (C) Nuclear energy  

      (D) Charcoal 

      

Q4. Name the two renewable source of energy.   

(i) Solar energy

(ii) Wind energy 

(iii) Hydro energy

 

Q5. Why is tungsten used almost exclusively for filament of electric lamps?   

Tungsten is an alloy which has a very high melting point and very high resistivity so it does not burn or melt easily at a high temperature. When a current is passed through it, it becomes hot and emits light. 

 

Q6. What are advantages of water stored in ground? 

(i) It does not evaporate

(ii) It recharges wells near the area

(iii) It provides moisture to the vegetation

(iv) It does not provide breeding grounds for mosquitos, like stagnant water in lakes and ponds

(v) It is relatively protected from contamination by animal and human waste. 

 

Q7. Write the name of colours in sequence found after splitting of white light passing through a glass prism.  

Violet, Indigo, Blue, Green, Yellow, Orange, Red  (VIBGYOR)

 

Q8(a) Write two properties of magnetic lines of force. 

(i) They never cross one another. 

(ii) They flow from the south pole to the north pole within the magnet and north pole to south pole outside the magnet. 

 

(iii) The magnetic lines of force come closer to one another near the poles of a magnet but they are widely separated at other places. 

(b) State and explain Fleming’s left-hand rule.  

When a current-carrying conductor is placed in an external magnetic field, the conductor experiences a force perpendicular to both the field and to the direction of the current flow. It was invented by John Ambrose Fleming. 

 

Q9. Draw ray diagram and write nature of image formed if an object is placed at : 

(a) Between F and 2F of a concave lens.    

Position of image – between the principal focal point on the object side and the concave lens. 

Size of image – smaller than size of object

 

Nature of image – image is erect and virtual

(b) Between F and 2F of a convex lens.    

Position of image – image is beyond 2F

Size of image – larger than size of object

Nature of image – image is inverted and real

 

 

Q10. Which of the following is chemical formula of bleaching powder?  

      (A) CaO  

      (B) CaOCl2  

      (C) Ca(OH)2  

      (D) CaCl2 

 

Q11. What is rancidity?   

When fats and oils stay in open for long, they get oxidized and become rancid (old and stale), and their smell and taste change. This process is known as rancidity. For example, the taste and smell of butter or bread changes when kept for long.

 

Q12. Define electronegativity. 

The tendency of an atom in a molecule to attract the shared pair of electrons towards itself is known as electronegativity. Electronegativity has no unit as it has no quantity. It is measured on a scale, called the Pauling scale. Fluorine is the most electronegative element and cesium is the least electronegative element.

 

Q13. Why is respiration considered as exothermic reaction? Explain. 

Exothermic reaction is a reaction in which energy is released in the form of heat or light. Respiration is considered as exothermic reaction because energy is released in this process.

During respiration, Carbohydrates present in food are broken down to form glucose. Glucose combines with oxygen in the cells of our body and provides energy. Therefore, respiration is an exothermic reaction. 

C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy 

 

 

Q14. Give two important uses of washing soda and baking soda.  

Uses of Washing Soda : It is used as a laboratory reagent. It is used in removing stains. It is used in removing the permanent hardness of the water. It is used in the manufacturing of soap, paper as well as glass. It is also used in textiles and petroleum refining. Chemical formula of Washing Soda is Na2CO3.10H2O 

 

Uses of Baking Soda : It reduces the acidity in the stomach. It is acts as an antacid which is used to treat stomach upset and indigestion. It is used in the process of washing as a water softener. Due to the formation of soapy foam, it is used in fire extinguishers. Chemical formula of Baking Soda is NaHCO3. 

 

Q15. In modern periodic table how does atomic size vary on moving down top to bottom in a group? Write its reason.  

The atomic size increases down the group. This is because new shells are added as we go down the group. This increase the distance between outermost electrons and the nucleus. Hence atomic size increases in spite of increase in nuclear charge. 

 

Q16(a) What are amphoteric oxides? Give two examples. 

The oxides which have a tendency to react with both acid and base to form salt and water are known as amphoteric oxides. Example- Aluminium oxide (Al2O3) and Zinc oxide (ZnO).

(b) Explain electrolytic refining. 

The impure metal is made the anode and a thin strip of pure metal is made the Cathode. A solution of metal salt is used as an electrolyte. On passing the current through the electrolyte, the pure metal from anode dissolves into the electrolyte. An equivalent amount of pure metal from the electrolyte is deposited on Cathode.  

 

Q17(a) What is homologous series? Explain with example. 

A series of organic compounds in which the some functional group substitutes for hydrogen in a carbon chain is called homologous series. 

eg. alkane homologous series (CH4 -Methane, C2H6 -Ethane, C3H8 -Propane, C4H10 -Butane …..) 

Properties :  Mol. mass of two consecutive members differ by 140. Two members differ by 2CH unit. Chemical properties remains same. Physical properties show regular variation. 

(b) Write the names of following compounds.  

      (i) CH3Br – Bromomethane

      (ii) CH3COCH3 – Propanone or Acetone 

      (iii)CH3CHO – Ethanal or Acetaldehyde 

                                       OR 

Explain the mechanism of cleaning action of soap. 

Most dist is oily in nature and oil does not dissolve in water. The molecules of soap are sodium or potassium salt of long chain carboxylic acid. The ionic end of soap dissolves in water while the carbon chain dissolves in oil. The soap molecules form structures called miscelle. In miscelle one part of molecule is towards oil droplet while the ionic end faces outside. This forms an emulsion in water. The soap miscelle thus helps in dissolving the dirt in water and we can wash our clothes clean. 

                  Formation of miscelles 

 

 

Q18. Which of the following hormone inhibits growth?   

      (A) Auxin   

      (B) Cytokinin   

      (C) Abscisic acid   

      (D) Gibberellin  

      

Q19. Which of the following is non-biodegradable?  

      (A) Glass   

      (B) Grass   

      (C) Paper   

      (D) None of these  

      

Q20. Placenta helps in transferring of :    

      (A) Oxygen     

      (B) Glucose     

      (C) Waste substances   

      (D) All of these  

      

Q21. Write full form of UNEP.  

United Nations Environment Programme

 

Q22. What is geotropism?         

The movement of plant parts in response to the direction of gravity is known as geotropism. The growth of plant roots is an example of geotropism as it grows towards the direction of gravity.

 

Q23. Explain any two contraceptive methods. 

Contraception is an artificial method or technique, mainly used to prevent pregnancy. 

Contraceptive methods : 

(i) Barrier method : In this method physical devices like condom, cervical caps and diaphragm are used to prevent sperms to reach up to the ovum.

(ii) Chemical method : In this method specific drugs are used by females like oral pills. Oral pills mainly contain hormones and are called oral contraceptives.

 

(iii) Surgical method: This method is applicable to both male and female. In males, a small portion of vas deferens and the fallopian tube in female is surgically removed or ligated (tied). It is known as vasectomy in males which prevents release of sperms from the testes. In females, it is called tubectomy.

 

Q24. Draw a well labelled diagram of longitudinal section of flower.   

The diagram depicts the cross-section of a flower taken along its longitudinal axis. The flower is made up of both male and female reproductive parts, hence the name “dioecious.” The pistil or carpel is the part of the flower that is responsible for female reproduction. Each carpel includes an ovary, as well as a stigma and a style. Stamens are the name given to the male reproductive parts of a flower. 

 

 

 

Q25. Write the functions of cerebellum and medulla.     

Function of Cerebellum : The cerebellum receives information from the sensory systems, the spinal cord and other parts of the brain and regulates the motor movements. It controls the voluntary movements such as posture, balance, coordination, and speech to maintain a smooth and balanced muscular activity. 

 

Function of Medulla : Medulla directly controls many involuntary responses like sneezing and blinking of eye. It controls our overall major motor functions, or body movement. It carries out blood vessel dilation to increase or decrease oxygen flow and respond to heart function. Other functions include digestion, swallowing and vomiting to get rid of bacteria or pathogens that could harm us.

 

Q26. Describe evolution of human beings.   

Human evolution is the evolutionary process by which human beings developed on earth. The evolution step involves a sequence of changes in genetic material and adapting to its surrounding. They evolved to live their lives to the best of their abilities. 

Stages in human evolution –

Dryopethicus : The earlier known ancestor of man. Found in some parts of Africa, Asia, and Europe.

Australopithecus : Inhabited in the mainland of Asia. Have large jaws and human-like teeth.

Homo habilis : Make use of stone tools. They are able to communicate with each other.

Homo erectus : More-evolved human beings with large brain sizes. Invented fire and were carnivorous (eat meat)

 

Homo sapiens : These are modern men with 1350cc brain capacity. Develop the power of thinking, using tools, and being omnivorous.

 

Q27(a) Write three differences between autotrophic and heterotrophic nutrition.         

Autotrophic Nutrition : Autotrophic nutrition is a process where an organism prepares its own food from a simple inorganic material like water, mineral salts and carbon dioxide in the presence of sunlight. 

 

Heterotrophic Nutrition : Heterotrophic nutrition is the mode of nutrition where the organism is unable to prepare its food and hence, depends upon plants or other organisms for nutrition.  

(b) How is oxygen and carbon-dioxide transported in human beings? 

Haemoglobin present in blood aids in the transportation of these gases.The blood serves as a transport system for both carbon dioxide and oxygen. Oxygen is carried to the cells whereas carbon dioxide is carried away from the cells.

Transport of oxygen : The oxygen molecule can bind to the haemoglobin molecules easily.One molecule of haemoglobin binds four molecules of oxygen.Haemoglobin present in the blood takes up the oxygen from the air in the lungs. It carries the oxygen to tissues which are deficient in oxygen before releasing it.

 

Transport of carbon dioxide : Carbon dioxide is more soluble in water. Therefore, it is mostly transported from body tissues in the dissolved form in our blood plasma to lungs in the form of carboxyhemoglobin. Here it diffuses from blood to air in the lungs.

                                     OR                                       

Describe structure and functioning of nephron.  

Structure of nephron : A nephron is the filtration unit of the kidney. It consists of a tubule which is connected with collecting duct at one end and a cup-shaped structure at the other end. This filtrate contains glucose, amino acids, urea, uric acid, salts and a major amount of water.

Functioning of nephron : A nephron is the fundamental part of the structure in the kidney. A nephron separates water, ions and small molecules from the blood and purifies out wastes and toxins from them and then deliver desired molecules to the blood. The nephron functions through ultra-filtration. The nephron is the basic functional and structural unit of the kidney. Its main purpose is to monitor the consistency of water and dis-solvable substances like sodium salts by infiltrating the blood, reabsorbing what is required and eliminating the rest as urine.