Bihar Board Class 10 · Science · Matric exam 2027
Bihar Board Class 10 Science Question Paper 2023
The board’s 2023 question paper, set H — all 106 questions as printed; 75 objective answers from the board’s own key; full model answers for 3 written questions, how the answer begins for 27 more. Each question names its chapter, where that chapter’s most-asked questions are.
Full marks 80 · Time 2 h 45 min
Section A · Objective questions (76)
What is the chemical formula of washing soda ?
- (A) NaHCO_3
- (B) Na_2CO_3.10 H_2O ✓
- (C) KNO_3
- (D) CH_3COOH
Answer (the board’s key): (B)
Which of the following is a non-metal ?
- (A) Cu
- (B) P ✓
- (C) Fe
- (D) Ni
Answer (the board’s key): (B)
What is the atomic number of calcium ?
- (A) 12
- (B) 18
- (C) 20 ✓
- (D) 25
Answer (the board’s key): (C)
How many groups are there in the Mendeleev's periodic table ?
- (A) 10
- (B) 9
- (C) 8 ✓
- (D) 7
Answer (the board’s key): (C)
The chemical formula of gypsum is
- (A) FeSO_4.7H_2O
- (B) CaSO_4.1/2H_2O
- (C) CaSO_4.5H_2O
- (D) CaSO_4.2H_2O ✓
Answer (the board’s key): (D)
What is the atomic weight of Boron ?
- (A) 10
- (B) 11 ✓
- (C) 12
- (D) 13
Answer (the board’s key): (B)
Calamine is the ore of which of the following metals ?
- (A) Zn ✓
- (B) Al
- (C) Fe
- (D) Hg
Answer (the board’s key): (A)
The ratio of the atoms of nitrogen and hydrogen in a molecule of ammonia is
- (A) 3 : 1
- (B) 1 : 3 ✓
- (C) 2 : 1
- (D) 1 : 2
Answer (the board’s key): (B)
The component of blood responsible for transporting oxygen is
- (A) RBC ✓
- (B) WBC
- (C) Blood platelets
- (D) All of these
Answer (the board’s key): (A)
Vermiform appendix is a part of
- (A) Alimentary canal ✓
- (B) Nervous system
- (C) Vascular system
- (D) Reproductive system
Answer (the board’s key): (A)
The movement of shoot towards light is
- (A) Geotropism
- (B) Hydrotropism
- (C) Chemotropism
- (D) Phototropism ✓
Answer (the board’s key): (D)
The use of iodised salt is recommended to prevent
- (A) Diabetes
- (B) Goitre ✓
- (C) Hypertension
- (D) None of these
Answer (the board’s key): (B)
The number of cranial nerves present in human beings is
- (A) 12 pairs ✓
- (B) 31 pairs
- (C) 24 pairs
- (D) 10 pairs
Answer (the board’s key): (A)
In which part of the brain is the centre of smell recognition ?
- (A) Mid-brain
- (B) Fore-brain ✓
- (C) Hind-brain
- (D) None of these
Answer (the board’s key): (B)
Appearance of first menstruation is called
- (A) Menopause
- (B) Menarche ✓
- (C) Menstrual cycle
- (D) All of these
Answer (the board’s key): (B)
Which of the following is a method of artificial vegetative propagation ?
- (A) Cutting
- (B) Layering
- (C) Grafting
- (D) All of these ✓
Answer (the board’s key): (D)
The chemical showing biomagnification is
- (A) CFC
- (B) DDT ✓
- (C) NADP
- (D) ATP
Answer (the board’s key): (B)
The excretory substance(s) of plants is/are
- (A) Tannin
- (B) Gum
- (C) Resin
- (D) All of these ✓
Answer (the board’s key): (D)
The process of purification of blood by dialysis machine is called
- (A) dialysate
- (B) dialyser
- (C) cellophane
- (D) haemodialysis ✓
Answer (the board’s key): (D)
Which of the following is an example of geotropism ?
- (A) Growth of fruit
- (B) Growth of root ✓
- (C) Growth of flower
- (D) None of these
Answer (the board’s key): (B)
The fully developed ovary is called as
- (A) fruit ✓
- (B) seed
- (C) ovule
- (D) none of these
Answer (the board’s key): (A)
Sexually transmitted disease is
- (A) Jaundice
- (B) Chickenpox
- (C) AIDS ✓
- (D) Plague
Answer (the board’s key): (C)
Electromotive force of a cell is
- (A) the force exerted by the cell on unit charge
- (B) potential difference
- (C) the work done by the cell on unit charge
- (D) none of these
The flow of energy in an ecosystem is
- (A) unidirectional ✓
- (B) multidirectional
- (C) bidirectional
- (D) cyclic
Answer (the board’s key): (A)
The S.I. unit of charge is
- (A) ohm (Ω)
- (B) coulomb (C) ✓
- (C) ampere (A)
- (D) volt (V)
Answer (the board’s key): (B)
Eye with farsightedness can see clearly
- (A) near objects
- (B) far objects ✓
- (C) only small things
- (D) only big things
Answer (the board’s key): (B)
Which of the following energy sources is not a derivative of solar energy ?
- (A) Wind energy
- (B) Biomass
- (C) Geothermal energy
- (D) Nuclear energy ✓
Answer (the board’s key): (D)
Who discovered the magnetic effect of electric current ?
- (A) Faraday
- (B) Ampere
- (C) Bohr
- (D) Oersted ✓
Answer (the board’s key): (D)
In the coordinate sign convention, the focal length is positive for
- (A) convex lens
- (B) convex mirror
- (C) concave mirror
- (D) both (A) and (B) ✓
Answer (the board’s key): (D)
Due to which of the following reasons an aqueous solution of common salt is a good conductor of electricity ?
- (A) The motion of negative charge only
- (B) The motions of both positive and negative charges in opposite directions ✓
- (C) The motion of positive charge only
- (D) None of these
Answer (the board’s key): (B)
Which of the following is found in pollen sac ?
- (A) Stigma
- (B) Pollen grains ✓
- (C) Corolla
- (D) None of these
Answer (the board’s key): (B)
Which of the following is not a plant hormone ?
- (A) Auxin
- (B) Oxytocin ✓
- (C) Ethylene
- (D) Cytokinin
Answer (the board’s key): (B)
Which is a method of asexual reproduction ?
- (A) Sporogenesis
- (B) Budding
- (C) Fission
- (D) All of these ✓
Answer (the board’s key): (D)
Which plant did Mendel choose for his experiment ?
- (A) Pea ✓
- (B) Gram
- (C) Wheat
- (D) All of these
Answer (the board’s key): (A)
Who among the following is called the 'Father of Biology' ?
- (A) Lamarck
- (B) Aristotle ✓
- (C) Charles Darwin
- (D) Gregor Johann Mendel
Answer (the board’s key): (B)
The number of sex chromosomes in a human gamete is
- (A) 1 ✓
- (B) 2
- (C) 3
- (D) 4
Answer (the board’s key): (A)
What is the relation between angle of incidence (i != 0) and angle of refraction (r) in moving from a denser medium to a rare medium ?
- (A) i > r
- (B) i = r
- (C) r > i ✓
- (D) r = i = 0
Answer (the board’s key): (C)
All distances are measured in the coordinate sign convention
- (A) from centre of curvature
- (B) from pole ✓
- (C) from focus
- (D) none of these
Answer (the board’s key): (B)
Which of the following metals is solar cell made of ?
- (A) Gold
- (B) Silicon ✓
- (C) Zinc
- (D) Platinum
Answer (the board’s key): (B)
During short circuit, the resistance of the circuit
- (A) remains unchanged
- (B) becomes very low ✓
- (C) becomes very high
- (D) none of these
Answer (the board’s key): (B)
A potential difference of 100 V is applied across a ( 100 W, 220 V ) rated bulb. The current flowing will be
- (A) 25/121 A ✓
- (B) 1 A
- (C) 5/11 A
- (D) None of these
Answer (the board’s key): (A)
The material of the filament of an electric bulb is
- (A) nichrome
- (B) tungsten ✓
- (C) iron
- (D) none of these
Answer (the board’s key): (B)
The minimum wavelength of light is
- (A) 550 nm
- (B) 380 nm ✓
- (C) 100 nm
- (D) 760 nm
Answer (the board’s key): (B)
Due to electric resistance, conductors acquire
- (A) elasticity
- (B) magnetism
- (C) thermal effect ✓
- (D) none of these
Answer (the board’s key): (C)
The focal length of a spherical mirror is + 20 cm. What type of spherical mirror is this ?
- (A) Concave
- (B) Convex ✓
- (C) Both (A) and (B)
- (D) None of these
Answer (the board’s key): (B)
The image formed by a plane mirror is
- (A) Real
- (B) Virtual ✓
- (C) Both (A) and (B)
- (D) None of these
Answer (the board’s key): (B)
Which of the following is the mirror formula ?
- (A) 1/f = 1/v - 1/u
- (B) 1/f = 1/v + 1/u ✓
- (C) 1/f = 1/u - 1/v
- (D) None of these
Answer (the board’s key): (B)
The magnification produced by a plane mirror is
- (A) +1 ✓
- (B) -1
- (C) 0
- (D) None of these
Answer (the board’s key): (A)
In which of the following mirrors, can a virtual image of an object be obtained ?
- (A) By plane mirror
- (B) By convex mirror
- (C) By concave mirror
- (D) All of these ✓
Answer (the board’s key): (D)
The blue colour of the sky is the result of which phenomenon ?
- (A) Reflection
- (B) Refraction
- (C) Scattering ✓
- (D) None of these
Answer (the board’s key): (C)
A ray passing from a rarer medium to dense medium bends
- (A) towards normal ✓
- (B) away from normal
- (C) coincident with normal
- (D) none of these
Answer (the board’s key): (A)
Which of the following lenses has positive focal length ?
- (A) Convex lens ✓
- (B) Plano-concave lens
- (C) Concave lens
- (D) None of these
Answer (the board’s key): (A)
The solution of which pH value will be most alkaline ?
- (A) pH = 5
- (B) pH = 10
- (C) pH = 11 ✓
- (D) pH = 8
Answer (the board’s key): (C)
The chemical name of lime water is
- (A) Slaked lime
- (B) Calcium hydroxide ✓
- (C) Quicklime
- (D) Calcium oxide
Answer (the board’s key): (B)
Which of the following is the formula of soda ash ?
- (A) CaCl2
- (B) Na2CO3 ✓
- (C) NaCl
- (D) NaHCO3
Answer (the board’s key): (B)
Which of the following is the formula of Glauber's salt ?
- (A) Na2SO4.10 H2O ✓
- (B) Na2SO4.7 H2O
- (C) Na2SO4.5 H2O
- (D) Na2SO4.2 H2O
Answer (the board’s key): (A)
Which of the following is a synthetic indicator ?
- (A) Turmeric
- (B) Red cabbage
- (C) Methyl orange ✓
- (D) Litmus paper
Answer (the board’s key): (C)
Which of the following substances burns without flame ?
- (A) Candle
- (B) Methane gas
- (C) Kerosine
- (D) Coal ✓
Answer (the board’s key): (D)
Which of the following takes place in oxidation ?
- (A) Removal of hydrogen
- (B) Loss of electron
- (C) Addition of oxygen
- (D) All of these ✓
Answer (the board’s key): (D)
Which gas is liberated at cathode in the electrolysis of water ?
- (A) Ozone
- (B) Hydrogen ✓
- (C) Oxygen
- (D) None of these
Answer (the board’s key): (B)
How many structure-isomers are possible for pentane whose molecular formula is C5H12 ?
- (A) 5
- (B) 4
- (C) 3 ✓
- (D) 2
Answer (the board’s key): (C)
Carbon is a member of which group of periodic table ?
- (A) 3
- (B) 13
- (C) 4
- (D) 14 ✓
Answer (the board’s key): (D)
Goitre disease develops due to
- (A) obesity
- (B) lack of sugar
- (C) iodine deficiency ✓
- (D) lack of blood
Answer (the board’s key): (C)
Stomata are mainly found on
- (A) roots
- (B) leaves ✓
- (C) stems
- (D) none of these
Answer (the board’s key): (B)
The device for measuring blood pressure is called
- (A) stethoscope
- (B) lactometer
- (C) ammeter
- (D) sphygmomanometer ✓
Answer (the board’s key): (D)
What is found in anther ?
- (A) Ovary
- (B) Corolla
- (C) Gynoecium
- (D) Pollen grains ✓
Answer (the board’s key): (D)
The colour of lymph is
- (A) green
- (B) red
- (C) light blue
- (D) light yellow ✓
Answer (the board’s key): (D)
Which among the following is a non-biodegradable material ?
- (A) Paper
- (B) Sewage
- (C) Wood
- (D) DDT ✓
Answer (the board’s key): (D)
Which of the following non-metals is a good conductor of electricity ?
- (A) Chlorine
- (B) Graphite ✓
- (C) Phosphorus
- (D) Sulphur
Answer (the board’s key): (B)
Which of the following is the most reactive metal in the reactivity series ?
- (A) Na ✓
- (B) Cu
- (C) Au
- (D) Hg
Answer (the board’s key): (A)
Pure gold is of how many carats ?
- (A) 20 carats
- (B) 22 carats
- (C) 24 carats ✓
- (D) 26 carats
Answer (the board’s key): (C)
Which of the following metals is kept immersed in kerosene ?
- (A) Sodium ✓
- (B) Magnesium
- (C) Tungsten
- (D) Mercury
Answer (the board’s key): (A)
Which of the following is produced in aqueous solution of an acid ?
- (A) OH- ions
- (B) H+ ions ✓
- (C) H3O- ions
- (D) H2O+ ions
Answer (the board’s key): (B)
Which of the following is the strongest acid ?
- (A) HF
- (B) HCl
- (C) HBr
- (D) HI ✓
Answer (the board’s key): (D)
The pH value of pure water is
- (A) 0
- (B) 5
- (C) 7 ✓
- (D) 14
Answer (the board’s key): (C)
An aqueous solution of which of the following substances turns blue litmus paper into red ?
- (A) Acid ✓
- (B) Base
- (C) Salt
- (D) None of these
Answer (the board’s key): (A)
Section B · Written questions (30)
What do you mean by nuclear energy ?
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Model answer · nuclear energy, definition
- 1.Nuclear energy is the energy obtained from the process of fission or fusion of the atomic nucleus. In nuclear fission, the nucleus of a heavy atom such as uranium, plutonium or thorium is split apart into lighter nuclei when bombarded with low-energy neutrons. In nuclear fusion, lighter nuclei join together to make a heavier nucleus.1 mark
- 2.In this process, mass is converted into energy, which generates a large amount of heat. The difference in mass, Δm, between the original nucleus and the product nuclei gets converted to energy E according to the equation E = Δm c2, where c is the speed of light in vacuum.1 mark
- Mention both 'fission' and 'fusion' of the atomic nucleus.
- State that mass is converted into energy and a large amount of heat is generated.
- Write the equation E = Δm c2 to show mass-energy conversion.
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
On which factors does the resistance of a conductor depend ?
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Model answer · factors affecting resistance
- 1.The resistance of a conductor is directly proportional to its length (l), that is, R ∝ l.0.5 marks
- 2.The resistance of a conductor is inversely proportional to its area of cross-section (A), that is, R ∝ 1/A.0.5 marks
- 3.The resistance of a conductor depends on the nature of its material, given by R = ρl/A, where ρ (rho) is the electrical resistivity of the material.0.5 marks
- 4.The resistance of a conductor depends on the temperature. Both the resistance and resistivity of a material vary with temperature.0.5 marks
- Write R ∝ l for length and R ∝ 1/A for area of cross-section as separate points.
- Name 'nature of its material' and give the formula R = ρl/A with ρ as resistivity.
- State that resistance and resistivity vary with temperature.
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
What is defect of vision ? How many are its types ?
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Model answer · defects of vision, types
- 1.Defect of vision is the condition in which the eye may gradually lose its power of accommodation, so that the person cannot see the objects distinctly and comfortably. The vision becomes blurred due to the refractive defects of the eye.1 mark
- 2.There are mainly three common refractive defects of vision. These are (i) myopia or near-sightedness, (ii) Hypermetropia or far-sightedness, and (iii) Presbyopia. These defects can be corrected by the use of suitable spherical lenses.1 mark
- Write that the eye loses its power of accommodation and vision becomes blurred due to refractive defects of the eye.
- Name all three types exactly: myopia, hypermetropia and presbyopia.
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
Define electric potential and write its S.I. unit.
How the model answer begins
1. Electric potential at a point is defined as the work done in bringing a unit positive charge from infinity to that point.
The full answer from Medha Ma’am →Why is a concave lens called a diverging lens ?
How the model answer begins
1. A concave lens spreads out the light rays coming parallel to its principal axis after refraction. Several rays of light parallel to the principal axis fall on a concave lens, and these rays, after refraction from the…
The full answer from Medha Ma’am →What are the benefits of generating electricity from solar cell ?
How the model answer begins
1. Generating electricity from solar cells is pollution-free. Solar cells convert solar energy into electricity directly and do not cause any pollution, unlike devices that burn fossil fuels, making them…
The full answer from Medha Ma’am →Why is it necessary to earth metal casing electrical appliances ?
How the model answer begins
1. Earthing metal-cased electrical appliances means connecting the metallic body of the appliance to the earth wire, which provides a low-resistance conducting path for the current. This ensures that any leakage of current…
The full answer from Medha Ma’am →What are the drawbacks of fossil fuels ?
How the model answer begins
1. Burning of fossil fuels causes air pollution because the oxides of carbon, nitrogen and sulphur that are released on burning fossil fuels are acidic oxides. These lead to acid rain which affects our water and soil…
The full answer from Medha Ma’am →What is the process of accommodation of human eye ? Explain it.
How the model answer begins
1. The ability of the eye lens to adjust its focal length is called accommodation. The eye lens is composed of a fibrous, jelly-like material and its curvature can be modified to some extent by the ciliary muscles. The…
The full answer from Medha Ma’am →Which type of iron is used in electromagnet and permanent magnet ? Explain the difference between both types of magnet.
How the model answer begins
1. Soft iron is used to make an electromagnet. A current-carrying solenoid can be used to magnetise a piece of magnetic material, like soft iron, when placed inside the coil, and the magnet so formed is called an…
The full answer from Medha Ma’am →Identify the substances that are oxidised and reduced in the following reactions :- i) 4Na (s) + O2 (g) -> 2Na2O (s) ii) CuO (s) + H2 (g) -> Cu (s) + H2O (l)
How the model answer begins
1. In reaction (i), 4Na(s) + O2(g) → 2Na2O(s), Sodium (Na) is oxidised because oxygen is added to it to form Na2O.
The full answer from Medha Ma’am →Why does an acid not show acidic behaviour in the absence of water ?
How the model answer begins
1. The separation of H+ ion from an acid molecule cannot occur in the absence of water, so acids are unable to produce hydrogen ions (H+) without water. For example, HCl + H2O → H3O+ + Cl–. Hydrogen ions cannot exist…
The full answer from Medha Ma’am →Why do compounds like alcohol and glucose not show acidic character in aqueous solution?
How the model answer begins
1. Molecules of alcohol and glucose contain hydrogen atoms, but they do not produce H+ ions in aqueous solution.
The full answer from Medha Ma’am →While diluting an acid, acid should be added to water and not water to acid. Why?
How the model answer begins
1. The process of dissolving an acid in water is a highly exothermic one, which means a large amount of heat is released when an acid is mixed with water.
The full answer from Medha Ma’am →How is an alloy prepared from gold ?
How the model answer begins
1. Pure gold, known as 24 carat gold, is very soft and is, therefore, not suitable for making jewellery. So it is alloyed with either silver or copper to make it hard.
The full answer from Medha Ma’am →Show the electron dot structure of carbon dioxide (CO2).
How the model answer begins
1. Carbon has 4 electrons and each oxygen 6 electrons in the outermost shell, shown as dots in the structure.
The full answer from Medha Ma’am →What is a detergent? Give an example.
How the model answer begins
1. Detergents are generally ammonium or sulphonate salts of long chain carboxylic acids. The charged ends of these compounds do not form insoluble precipitates with the calcium and magnesium ions in hard water. Thus, they…
The full answer from Medha Ma’am →What are the short periods and long periods of the periodic table? Write their number.
How the model answer begins
1. Short periods have fewer elements: periods 1, 2 and 3 — 3 short periods (2 elements in the first, 8 each in the second and third).
The full answer from Medha Ma’am →What do you understand by saponification? Explain. How is it different from esterification?
How the model answer begins
1. Saponification is the process of forming soap and glycerol by heating esters of higher fatty acids with sodium hydroxide or potassium hydroxide. When an ester is treated with sodium hydroxide, which is an alkali, the…
The full answer from Medha Ma’am →What is a chemical equation ? What information are obtained from the following equation ? 2SO2 + O2 -> 2SO3
How the model answer begins
1. Representing a chemical reaction in a concise form using symbols and formulas is called a chemical equation.
The full answer from Medha Ma’am →What is the function of umbilical cord ?
How the model answer begins
1. The umbilical cord provides nutrition and oxygen to the fetus from the mother's blood. This happens with the help of a special tissue called placenta, which gives a large surface area for glucose and oxygen to pass from…
The full answer from Medha Ma’am →What is heterotrophic nutrition ?
How the model answer begins
1. Heterotrophic nutrition is a process in which organisms do not synthesize their own food but obtain it from other sources.
The full answer from Medha Ma’am →What is the difference between autotrophic and heterotrophic nutrition ?
How the model answer begins
1. Autotrophic nutrition is the mode of nutrition in which organisms use simple food material obtained from inorganic sources in the form of carbon dioxide and water to synthesize their own food. The autotrophs include…
The full answer from Medha Ma’am →What is villi ? Write its function.
How the model answer begins
1. Villi are the numerous finger-like projections present on the inner lining of the small intestine.
The full answer from Medha Ma’am →What is the role of acid in our stomach ?
How the model answer begins
1. Hydrochloric acid present in the stomach kills the harmful bacteria present in the food that we eat, thus protecting the body from infection.
The full answer from Medha Ma’am →What is blood ? Which component of it is helpful in gaseous transport ?
How the model answer begins
1. Blood is a fluid connective tissue that performs the function of transporting substances in the body. Blood consists of a fluid medium called plasma in which the cells are suspended. These cells include red blood…
The full answer from Medha Ma’am →Define hormones.
How the model answer begins
1. A hormone is a chemical substance secreted by an endocrine gland that regulates specific functions of the body.
The full answer from Medha Ma’am →What is greenhouse effect ?
How the model answer begins
1. The greenhouse effect is the process by which the atmosphere of the earth traps the heat coming from the sun and keeps the earth warm.
The full answer from Medha Ma’am →Explain the fertilisation process in flowering plants with a diagram.
How the model answer begins
1. After pollination the pollen grain lands on the stigma, germinates and forms a pollen tube.
The full answer from Medha Ma’am →Describe the process of respiration in human.
How the model answer begins
1. During respiration, air is taken into the body through the nostrils. The air passing through the nostrils is filtered by fine hairs that line the passage. The passage is also lined with mucus which helps in this…
The full answer from Medha Ma’am →
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