Bihar Board Class 10 · Science · Matric exam 2027
Bihar Board Class 10 Science Question Paper 2025
The board’s 2025 question paper, set D — all 110 questions as printed; 80 objective answers from the board’s own key; full model answers for 3 written questions, how the answer begins for 26 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 (80)
A horizontal magnet hanging freely in air always comes to rest in
- (A) Any direction
- (B) East-West direction
- (C) North-South direction ✓
- (D) None of these
Answer (the board’s key): (C)
If a compass is placed near a wire carrying electric current, the compass needle
- (A) Will be deflected ✓
- (B) The current carrying wire will be deflected
- (C) Will not be deflected
- (D) None of these
Answer (the board’s key): (A)
Faraday made many revolutionary discoveries, including
- (A) Electromagnetic induction
- (B) Law of electrolysis
- (C) Both (A) and (B) ✓
- (D) None of these
Answer (the board’s key): (C)
An electric motor converts
- (A) Chemical energy into electrical energy
- (B) Electrical energy into mechanical energy ✓
- (C) Mechanical energy into electrical energy
- (D) Electrical energy into chemical energy
Answer (the board’s key): (B)
In Fleming's left-hand rule, the index finger of the left hand indicates
- (A) Direction of magnetic field ✓
- (B) Direction of electric force applied on the conductor
- (C) Direction of electric current flowing in the conductor
- (D) None of these
Answer (the board’s key): (A)
When electric current flows through a conducting wire, what type of magnetic field is generated above and below the wire?
- (A) Opposite type ✓
- (B) Similar type
- (C) Not of any kind
- (D) None of these
Answer (the board’s key): (A)
What type of energy source is hydroelectric energy?
- (A) Renewable ✓
- (B) Non-renewable
- (C) Both (A) and (B)
- (D) None of these
Answer (the board’s key): (A)
Which gas is responsible for global warming?
- (A) Nitrogen
- (B) Carbon dioxide ✓
- (C) Oxygen
- (D) None of these
Answer (the board’s key): (B)
Bile juice is secreted by
- (A) Oral cavity
- (B) Liver ✓
- (C) Small intestine
- (D) Stomach
Answer (the board’s key): (B)
What is the function of the villi located in small intestine?
- (A) Blocking absorption
- (B) Reducing the surface area of absorption
- (C) Increasing the surface area of absorption ✓
- (D) None of these
Answer (the board’s key): (C)
The posterior part of the oral cavity is
- (A) Esophagus
- (B) Pharynx ✓
- (C) Duodenum
- (D) Pancreas
Answer (the board’s key): (B)
The transfer of O2 from outside environment to cells and removal of CO2 is referred to as
- (A) Exhalation
- (B) Respiration ✓
- (C) Inhalation
- (D) None of these
Answer (the board’s key): (B)
The basic source of oxygen in photosynthesis is
- (A) Chlorophyll
- (B) CO2
- (C) Water ✓
- (D) Solar energy
Answer (the board’s key): (C)
Which of the following is known as the 'energy currency' of the cell?
- (A) ATP ✓
- (B) ADP
- (C) DTP
- (D) None of these
Answer (the board’s key): (A)
Xylem in plant is responsible for
- (A) Carrying of food
- (B) Carrying of oxygen
- (C) Carrying of amino acid
- (D) Carrying of water ✓
Answer (the board’s key): (D)
Apart from plasma, which of the following is found in blood?
- (A) White Blood Cells (WBC)
- (B) Red Blood Cells (RBC)
- (C) Blood platelets
- (D) All of these ✓
Answer (the board’s key): (D)
An aqueous solution of acid conducts electricity, because acid in water
- (A) gets ionized ✓
- (B) is soluble
- (C) is insoluble
- (D) none of these
Answer (the board’s key): (A)
Which of the following is not an olfactory indicator?
- (A) Clove oil
- (B) Vanilla
- (C) Sweet potato ✓
- (D) All of these
Answer (the board’s key): (C)
Which acid is found in ant sting?
- (A) Citric acid
- (B) Acetic acid
- (C) Methanoic acid ✓
- (D) None of these
Answer (the board’s key): (C)
Which of the following is kept immersed in water?
- (A) White phosphorus ✓
- (B) Red phosphorus
- (C) Iodine
- (D) Sulphur
Answer (the board’s key): (A)
The substances, present as impurities in an ore, are called
- (A) Slag
- (B) Gangue ✓
- (C) Mineral
- (D) None of these
Answer (the board’s key): (B)
Which of the following metals can be easily cut with a knife?
- (A) Na ✓
- (B) Cu
- (C) Ni
- (D) Al
Answer (the board’s key): (A)
Which metal is mixed with gold to make an alloy?
- (A) Fe
- (B) Cu ✓
- (C) Zn
- (D) Ag
Answer (the board’s key): (B)
Silicon is a/an
- (A) Non-metal
- (B) Metal
- (C) Alloy
- (D) Metalloid ✓
Answer (the board’s key): (D)
Double circulation is not found in
- (A) Frog
- (B) Fish ✓
- (C) Bird
- (D) Human
Answer (the board’s key): (B)
From where does urea enter the blood ?
- (A) Kidney
- (B) Lungs
- (C) Liver ✓
- (D) None of these
Answer (the board’s key): (C)
Where does glucose reabsorption occur ?
- (A) In PCT ✓
- (B) In DCT
- (C) In Henle's loop
- (D) All of these
Answer (the board’s key): (A)
The mechanism for removing harmful substances formed as a result of various activities from the body is called
- (A) Digestive system
- (B) Circulatory system
- (C) Excretory system ✓
- (D) Nervous system
Answer (the board’s key): (C)
What can happen due to spinal cord injury ?
- (A) Goitre
- (B) Dwarfism
- (C) Diabetes
- (D) Paralysis ✓
Answer (the board’s key): (D)
The largest gland in the human body is
- (A) Adrenal
- (B) Liver ✓
- (C) Ovary
- (D) Pancreas
Answer (the board’s key): (B)
Plant hormone is called
- (A) Pheromone
- (B) Phytohormone ✓
- (C) Enzyme
- (D) None of these
Answer (the board’s key): (B)
An example of vegetative propagation through leaves is
- (A) Onion
- (B) Potato
- (C) Rose
- (D) Bryophylum ✓
Answer (the board’s key): (D)
If the focal length of the lens is f and power is P then
- (A) f + P = 0.5
- (B) f x P = 1 ✓
- (C) P + f = 1
- (D) P + f = 2
Answer (the board’s key): (B)
Which part of camera acts like the retina of the eye ?
- (A) Aperture
- (B) Lens
- (C) Film ✓
- (D) Shutter
Answer (the board’s key): (C)
For a healthy human eye, the near point and far point are respectively
- (A) 0 and infinity
- (B) 25 cm and 250 cm
- (C) 25 cm and infinity ✓
- (D) 0 and 25 cm
Answer (the board’s key): (C)
To an astronaut standing on the moon, the sky appears to be
- (A) Red
- (B) Blue
- (C) Black ✓
- (D) White
Answer (the board’s key): (C)
The decreased accommodative ability of the eye causes
- (A) Farsightedness
- (B) Presbyopia ✓
- (C) Nearsightedness
- (D) Colourblindness
Answer (the board’s key): (B)
The unit of resistivity in a conductor is
- (A) Ω m ✓
- (B) Ω/m
- (C) Ω^-1
- (D) None of these
Answer (the board’s key): (A)
How many calories are there in 1 joule?
- (A) 0.23 ✓
- (B) 0.19
- (C) 0.21
- (D) 0.25
Answer (the board’s key): (A)
The filament in an electric bulb is made of which of the following metals?
- (A) Iron
- (B) Aluminium
- (C) Tungsten ✓
- (D) Copper
Answer (the board’s key): (C)
Changes occurring in adolescence are called
- (A) Diversity
- (B) Germination
- (C) Puberty ✓
- (D) None of these
Answer (the board’s key): (C)
Which of the following is an effective measure used in family planning?
- (A) Diaphragm
- (B) Condom
- (C) Copper T and loop
- (D) All of these ✓
Answer (the board’s key): (D)
What is the meaning of atavism?
- (A) Inheritance of parental characteristics in progeny
- (B) No inheritance of parental characteristics in progeny
- (C) Inheritance of ancestral characteristics in progeny, which are not in parents ✓
- (D) All of these
Answer (the board’s key): (C)
The genetic structure of an organism is called
- (A) Phenotype
- (B) Genotype ✓
- (C) Heredity
- (D) Diversity
Answer (the board’s key): (B)
The evolution of organisms by natural selection is called
- (A) Mendelism
- (B) Lamarckism
- (C) Micro-development
- (D) Darwinism ✓
Answer (the board’s key): (D)
The chemical which shows biomagnification is
- (A) CFC
- (B) ADP
- (C) ATP
- (D) DDT ✓
Answer (the board’s key): (D)
Primary consumers are called
- (A) Decomposer
- (B) Omnivorous
- (C) Carnivorous
- (D) Vegetarian ✓
Answer (the board’s key): (D)
CFC is widely used in
- (A) Jet engines
- (B) Refrigerators
- (C) Air conditioners
- (D) All of these ✓
Answer (the board’s key): (D)
How many isomers of butane are possible ?
- (A) 2 ✓
- (B) 3
- (C) 4
- (D) 5
Answer (the board’s key): (A)
The shape of methane molecule is
- (A) Linear
- (B) Annular
- (C) Tetrahedral ✓
- (D) Octahedral
Answer (the board’s key): (C)
The valency of carbon in organic compounds is
- (A) 1
- (B) 2
- (C) 3
- (D) 4 ✓
Answer (the board’s key): (D)
Which of the following is saturated hydrocarbon ?
- (A) Alkane ✓
- (B) Akene
- (C) Alkyne
- (D) None of these
Answer (the board’s key): (A)
IUPAC name of ethylene is
- (A) Ethane
- (B) Ethyne
- (C) Ethene ✓
- (D) None of these
Answer (the board’s key): (C)
Which was a defect of Mendeleev's periodic table ?
- (A) Not giving proper place to oxygen
- (B) Not giving proper place to Cl
- (C) Not giving proper place to hydrogen ✓
- (D) None of these
Answer (the board’s key): (C)
Who among the following propounded the laws of octave ?
- (A) Mendeleev
- (B) Newlands ✓
- (C) Lother Meyer
- (D) Dobereiner
Answer (the board’s key): (B)
Which of the following compounds would be the most basic ?
- (A) SO_2
- (B) Na_2O ✓
- (C) Al_2O_3
- (D) NO_2
Answer (the board’s key): (B)
A group of rays is called
- (A) Light beam
- (B) Ray beam
- (C) Both (A) and (B) ✓
- (D) None of these
Answer (the board’s key): (C)
The light rays travel in
- (A) any direction
- (B) oblique line
- (C) a straight line ✓
- (D) none of these
Answer (the board’s key): (C)
Which type of mirror is a concave mirror ?
- (A) Divergent
- (B) Convergent ✓
- (C) Both convergent and divergent
- (D) None of these
Answer (the board’s key): (B)
Which of the following types of mirror is used in the headlight of a car ?
- (A) Convex mirror
- (B) Concave mirror ✓
- (C) Plane mirror
- (D) None of these
Answer (the board’s key): (B)
The focal length of a concave mirror is
- (A) Positive
- (B) Negative ✓
- (C) both (A) and (B)
- (D) None of these
Answer (the board’s key): (B)
Which mirror always forms an image smaller than the object ?
- (A) Concave
- (B) Plane
- (C) Convex ✓
- (D) None of these
Answer (the board’s key): (C)
The speed of light in air as compared to vacuum is
- (A) Less ✓
- (B) More
- (C) Same
- (D) None of these
Answer (the board’s key): (A)
Which phenomenon exhibited by light is demonstrated in the twinkling of stars ?
- (A) Reflection
- (B) Dispersion
- (C) Scattering
- (D) Refraction ✓
Answer (the board’s key): (D)
In which state is the Kalpakkam Nuclear Power Plant located ?
- (A) Karnataka
- (B) Tamil Nadu ✓
- (C) Uttar Pradesh
- (D) Gujarat
Answer (the board’s key): (B)
The main component of domestic gas (LPG) is
- (A) Ethane
- (B) Propane
- (C) Butane ✓
- (D) Methane
Answer (the board’s key): (C)
The two non-renewable sources of energy are
- (A) Gobar gas and biomass
- (B) Coal and petroleum ✓
- (C) Biomass and petroleum
- (D) None of these
Answer (the board’s key): (B)
Which type of reaction is respiration ?
- (A) Combination
- (B) Reduction
- (C) Endothermic
- (D) Oxidation ✓
Answer (the board’s key): (D)
Compounds formed by transfer of electrons are called
- (A) Organic
- (B) Covalent
- (C) Electrovalent ✓
- (D) None of these
Answer (the board’s key): (C)
Which of the following reactions is an example of decomposition reaction ?
- (A) H2 + I2 -> 2HI
- (B) NH4CNO -> H2NCONH2
- (C) NaOH + HCl -> NaCl + H2O
- (D) 2KClO3 -> KCl + 3O2 ✓
Answer (the board’s key): (D)
In which of the following is tartaric acid found ?
- (A) Orange
- (B) Tamarind ✓
- (C) Tomato
- (D) Vinegar
Answer (the board’s key): (B)
What is the chemical name of slaked lime ?
- (A) Calcium oxychloride
- (B) Calcium chloride
- (C) Calcium oxide
- (D) Calcium hydroxide ✓
Answer (the board’s key): (D)
Magnesium is a member of which group of the periodic table ?
- (A) Group VIII
- (B) Group I
- (C) Group II ✓
- (D) Nonmetallic element
Answer (the board’s key): (C)
How many periods are there in the periodic table ?
- (A) 12
- (B) 9
- (C) 8
- (D) 7 ✓
Answer (the board’s key): (D)
Which of the following is not an ancient method of water harvesting ?
- (A) Katta
- (B) Kulh
- (C) Dug well
- (D) Irish ✓
Answer (the board’s key): (D)
What was the objective of construction of Tehri Dam ?
- (A) Electricity generation
- (B) Land irrigation
- (C) Water supply
- (D) All of these ✓
Answer (the board’s key): (D)
What is the new concept of waste management?
- (A) Reuse
- (B) Recycle
- (C) Reduce
- (D) All of these ✓
Answer (the board’s key): (D)
Which of the following is a renewable resource?
- (A) Coal
- (B) Forest ✓
- (C) Petroleum
- (D) None of these
Answer (the board’s key): (B)
Which of the following is the main component of biogas?
- (A) Carbon dioxide
- (B) Hydrogen sulphide
- (C) Water vapour
- (D) Methane ✓
Answer (the board’s key): (D)
Peptic ulcer can be caused by
- (A) Eating less food
- (B) Eating normal food
- (C) Prolonged starvation ✓
- (D) None of these
Answer (the board’s key): (C)
Section B · Written questions (30)
Why do planets not twinkle? Explain.
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Model answer · twinkling of stars and planets
- 1.The planets do not twinkle because the planets are much closer to the earth, and are thus seen as extended sources.1 mark
- 2.If we consider a planet as a collection of a large number of point-sized sources of light, the total variation in the amount of light entering our eye from all the individual point-sized sources will average out to zero, thereby nullifying the twinkling effect. Thus, the average value of change in the intensity of light coming from planets is zero.1 mark
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
What is called absolute refractive index?
Medha Ma’am
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Model answer · absolute refractive index, definition
- 1.The absolute refractive index of a medium is the ratio of the speed of light in vacuum to the speed of light in the medium. If the first medium is vacuum or air, the refractive index of the second medium found with respect to it is called the absolute refractive index of that medium.1 mark
- 2.Its mathematical formula is n = c/v, where c is the speed of light in air (vacuum) and v is the speed of light in the medium.1 mark
- Write the exact phrase 'ratio of the speed of light in vacuum to the speed of light in the medium'.
- Clearly write the formula n = c/v with c and v defined as the speed of light in vacuum/air and in the medium.
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
What is farsightedness?
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Model answer · hypermetropia (far-sightedness)
- 1.Hypermetropia is also known as far-sightedness. It is a vision defect in which a person can see distant objects clearly but cannot see nearby objects distinctly.1 mark
- 2.In this defect, the near point of the person is farther away from the normal near point of 25 cm, so the person has to keep reading material much beyond 25 cm from the eye for comfortable reading.1 mark
- Write the term 'Hypermetropia' and its synonym 'far-sightedness' at the start.
- State clearly that distant objects are seen clearly but nearby objects are not.
- Mention that the near point shifts farther than the normal near point of 25 cm.
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
What do you understand by electromagnetic induction?
How the model answer begins
1. When there is a relative motion between a coil and a magnet placed near the coil, the magnetic field associated with the coil changes, and due to this changing magnetic field, an electric current is induced in the coil.
The full answer from Medha Ma’am →Why is inert gas filled in electric bulb?
How the model answer begins
1. Inert gas is filled in the electric bulb to protect the tungsten filament from oxidation. When the filament is heated to a very high temperature, it would react with the oxygen present in air and get oxidised and burnt.…
The full answer from Medha Ma’am →What do you understand by potential difference?
How the model answer begins
1. The work done to move a unit positive charge from one point to another in an electric circuit is called the potential difference between those two points.
The full answer from Medha Ma’am →What is called the best source of energy?
How the model answer begins
1. A good source of energy is one which would do a large amount of work per unit volume or mass, that is, it has a high calorific value.
The full answer from Medha Ma’am →What is dynamo? What is its use?
How the model answer begins
1. A dynamo is a device that converts mechanical energy into electrical energy. It works on the basis of electromagnetic induction, in which mechanical energy is used to rotate a conductor in a magnetic field to produce…
The full answer from Medha Ma’am →What are defects of vision ? What are their types ? How are the defects resolved ?
How the model answer begins
1. A vision defect is a condition in which the eyes are unable to see objects clearly. Sometimes, the eye may gradually lose its power of accommodation, and in such conditions, the person cannot see the objects distinctly…
The full answer from Medha Ma’am →Describe the structure and working method of a biogas plant.
How the model answer begins
1. A biogas plant has a dome-like structure built with bricks. A slurry of cow-dung and water is made in the mixing tank from where it is fed into the digester.
The full answer from Medha Ma’am →Write three information obtained from chemical equation.
How the model answer begins
1. A chemical equation provides information about the names and chemical formulas of reactants and products taking part in a reaction.
The full answer from Medha Ma’am →Why is an aqueous solution of sodium carbonate alkaline ?
How the model answer begins
1. Sodium carbonate is a salt of a strong base and a weak acid, as it is formed from the reaction of a strong base, sodium hydroxide, and a weak acid, carbonic acid.
The full answer from Medha Ma’am →What is an indicator ? Write the name of an indicator.
How the model answer begins
1. Indicators are substances that indicate the presence of acid or base in a solution by a change in colour or odour.
The full answer from Medha Ma’am →What is the difference between an atom and an ion ?
How the model answer begins
1. An atom is electrically neutral because it contains an equal number of protons and electrons. Since the number of positive charges (protons) balances the number of negative charges (electrons), the atom as a whole has…
The full answer from Medha Ma’am →Define ores.
How the model answer begins
1. Minerals from which metals can be extracted easily and profitably are called ores.
The full answer from Medha Ma’am →Why have detergents replaced soap ?
How the model answer begins
1. Detergents have replaced soap because detergents can produce lather even in hard water. This is because the charged ends of detergents do not form insoluble precipitates with the calcium and magnesium ions present in…
The full answer from Medha Ma’am →What are fossil fuels ?
How the model answer begins
1. Fossil fuels are fuels formed from the remains of plants and animals buried deep inside the earth for millions of years. These fuels were formed over millions of years ago and there are only limited reserves, so fossil…
The full answer from Medha Ma’am →What do you understand by short and long periods of periodic table ?
How the model answer begins
1. The second and third periods of the periodic table are called short periods because they contain 8 elements each.
The full answer from Medha Ma’am →Differentiate between metals and non-metals on the basis of physical and chemical properties.
How the model answer begins
1. Metals, in their pure state, have a shining surface and this property is called metallic lustre. Metals are generally solids at room temperature. Non-metals have properties opposite to that of metals; they lack metallic…
The full answer from Medha Ma’am →What is energy crisis ? Mention the measures to resolve it.
How the model answer begins
1. Energy crisis is the condition created due to the imbalance between the demand for energy and its supply. Our energy requirements increase with our standard of living and with technological progress, our demand for…
The full answer from Medha Ma’am →Write the names of four organelles of a cell.
How the model answer begins
1. The names of four cell organelles are nucleus, mitochondria, ribosome, and Golgi apparatus. These cell organelles are present inside the cell and perform different functions necessary for the life processes of the…
The full answer from Medha Ma’am →Define respiration.
How the model answer begins
1. Respiration is the process in which glucose, a six-carbon molecule, is broken down within the cell through oxidising-reducing reactions, using oxygen taken from outside the body, to release energy for the various…
The full answer from Medha Ma’am →What is the difference between xylem and phloem ?
How the model answer begins
1. Xylem moves water and minerals obtained from the soil. In xylem tissue, vessels and tracheids of the roots, stems and leaves are interconnected to form a continuous system of water-conducting channels reaching all parts…
The full answer from Medha Ma’am →What is excretion ? Write the names of its two main parts.
How the model answer begins
1. Excretion is the biological process involved in the removal of harmful metabolic wastes from the body. These wastes are produced as a result of metabolic activities taking place in the body of organisms.
The full answer from Medha Ma’am →What is phototropism ?
How the model answer begins
1. The movement of plant parts in the direction of light is called phototropism. This is a type of movement which allows the plant to respond to the stimulus of light by growing or bending towards or away from it.
The full answer from Medha Ma’am →What is pollination ?
How is DNA the basis of heredity ?
How the model answer begins
1. DNA is located in the nucleus of the cell and is the information source for making proteins in the cell. During sexual reproduction, both parents contribute equally to the DNA of the progeny. Through this DNA copying,…
The full answer from Medha Ma’am →What are the harmful effects of aerosol chemicals ?
How the model answer begins
1. Aerosol chemicals such as chlorofluorocarbons (CFCs) destroy the ozone layer present at the higher levels of the atmosphere. The ozone layer shields the surface of the earth from ultraviolet (UV) radiation from the Sun,…
The full answer from Medha Ma’am →What is photosynthesis ? Describe it with a suitable diagram.
How the model answer begins
1. Photosynthesis is the process by which green plants make their own food (glucose) using carbon dioxide and water in the presence of sunlight and chlorophyll. The plant takes up carbon dioxide from the air and water from…
The full answer from Medha Ma’am →Explain recycling of waste materials with examples.
How the model answer begins
1. Recycling of waste materials is the process in which useless items of waste like plastic, paper, glass and metal are collected and converted into useful substances instead of throwing them away. In order to recycle, we…
The full answer from Medha Ma’am →
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