Agniveer (Indian Army) CEE — Science Practice (100 Questions)
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Subject:Science
Q1. [+1, -0.25]Science
What is the SI unit of power?
A. Joule
B. Watt
C. Newton
D. Pascal
Correct Answer: B The Watt (W) is the SI unit of power, defined as one joule per second (1 W = 1 J/s).
Q2. [+1, -0.25]Science
Newton’s first law of motion is also known as the law of:
A. Inertia
B. Acceleration
C. Action and reaction
D. Gravitation
Correct Answer: A Newton’s first law states that an object at rest stays at rest and an object in motion stays in motion unless acted upon by an external force — this is the law of inertia.
Q3. [+1, -0.25]Science
Which element has the chemical symbol ‘Fe’?
A. Francium
B. Iron
C. Fluorine
D. Fermium
Correct Answer: B Fe is the chemical symbol for Iron, derived from the Latin word ‘Ferrum’.
Q4. [+1, -0.25]Science
What is the largest organ in the human body?
A. Liver
B. Skin
C. Lungs
D. Heart
Correct Answer: B The skin is the largest organ in the human body, covering an area of about 1.5–2 square meters.
Q5. [+1, -0.25]Science
Which type of lens converges light rays?
A. Convex lens
B. Concave lens
C. Plano-concave lens
D. Biconcave lens
Correct Answer: A A convex lens is thicker at the centre than at the edges and converges light rays to a focal point.
Q6. [+1, -0.25]Science
The atomic number of oxygen is:
A. 6
B. 7
C. 8
D. 16
Correct Answer: C Oxygen has atomic number 8, meaning it has 8 protons in its nucleus.
Q7. [+1, -0.25]Science
How many bones are there in an adult human skeleton?
A. 200
B. 206
C. 212
D. 300
Correct Answer: B An adult human has 206 bones. Infants have about 270 bones that fuse as they grow.
Q8. [+1, -0.25]Science
What is the chemical formula of sulphuric acid?
A. H2SO3
B. H2SO4
C. H2S
D. SO2
Correct Answer: B Sulphuric acid is H2SO4, a strong mineral acid widely used in industry.
Q9. [+1, -0.25]Science
Which vitamin is essential for blood clotting?
A. Vitamin A
B. Vitamin E
C. Vitamin K
D. Vitamin B12
Correct Answer: C Vitamin K is required for the synthesis of clotting factors in the liver.
Q10. [+1, -0.25]Science
What is the unit of electrical resistance?
A. Volt
B. Ohm
C. Ampere
D. Coulomb
Correct Answer: B The Ohm (Ω) is the SI unit of electrical resistance, named after Georg Ohm.
Q11. [+1, -0.25]Science
What is the powerhouse of the cell?
A. Nucleus
B. Mitochondria
C. Ribosome
D. Golgi apparatus
Correct Answer: B Mitochondria generate most of the cell’s ATP through oxidative phosphorylation, hence called the powerhouse.
Q12. [+1, -0.25]Science
Which element is a liquid metal at room temperature?
A. Gold
B. Mercury
C. Silver
D. Copper
Correct Answer: B Mercury (Hg) is the only metal that is liquid at standard room temperature and pressure.
Q13. [+1, -0.25]Science
The bending of light as it passes from one medium to another is called:
A. Reflection
B. Refraction
C. Diffraction
D. Dispersion
Correct Answer: B Refraction is the bending of light due to a change in its speed when moving between different media.
Q14. [+1, -0.25]Science
Which part of the human eye controls the amount of light entering?
A. Retina
B. Iris
C. Pupil
D. Cornea
Correct Answer: B The iris is the coloured part of the eye that contracts or dilates the pupil to control light entry.
Q15. [+1, -0.25]Science
What is the chemical formula of methane?
A. CH4
B. C2H6
C. CO2
D. C2H4
Correct Answer: A Methane (CH4) is the simplest hydrocarbon with one carbon atom bonded to four hydrogen atoms.
Q16. [+1, -0.25]Science
Which gas is produced when a metal reacts with an acid?
A. Oxygen
B. Hydrogen
C. Nitrogen
D. Chlorine
Correct Answer: B Metals react with acids to produce salt and hydrogen gas (H2).
Q17. [+1, -0.25]Science
The SI unit of pressure is:
A. Newton
B. Pascal
C. Bar
D. Joule
Correct Answer: B The Pascal (Pa) is the SI unit of pressure, defined as one newton per square metre.
Q18. [+1, -0.25]Science
What is the function of red blood cells?
A. Fight infections
B. Transport oxygen
C. Clot blood
D. Produce antibodies
Correct Answer: B Red blood cells (erythrocytes) contain haemoglobin which binds oxygen for transport throughout the body.
Q19. [+1, -0.25]Science
Which law states that energy cannot be created or destroyed?
A. Newton’s first law
B. Law of conservation of energy
C. Law of gravitation
D. Charles’s law
Correct Answer: B The law of conservation of energy states that energy can neither be created nor destroyed, only transformed.
Q20. [+1, -0.25]Science
Which disease is caused by a deficiency of iron?
A. Scurvy
B. Anaemia
C. Rickets
D. Beriberi
Correct Answer: B Iron deficiency leads to anaemia, characterised by reduced haemoglobin and fatigue.
Q21. [+1, -0.25]Science
What is the chemical name of baking soda?
A. Sodium carbonate
B. Sodium bicarbonate
C. Sodium chloride
D. Sodium hydroxide
Correct Answer: B Baking soda is sodium bicarbonate (NaHCO3), used as a leavening agent.
Q22. [+1, -0.25]Science
Which mirror is used in car rear-view mirrors?
A. Plane mirror
B. Concave mirror
C. Convex mirror
D. Parabolic mirror
Correct Answer: C Convex mirrors produce a diminished, upright virtual image with a wider field of view.
Q23. [+1, -0.25]Science
What is the scientific name of humans?
A. Homo erectus
B. Homo sapiens
C. Homo habilis
D. Homo neanderthalensis
Correct Answer: B Homo sapiens is the binomial nomenclature for modern humans.
Q24. [+1, -0.25]Science
Which gas is known as ‘laughing gas’?
A. Nitrogen dioxide
B. Nitrous oxide
C. Nitric oxide
D. Ammonia
Correct Answer: B Nitrous oxide (N2O) is known as laughing gas due to its euphoric effects when inhaled.
Q25. [+1, -0.25]Science
What is the SI unit of frequency?
A. Decibel
B. Hertz
C. Watt
D. Joule
Correct Answer: B The Hertz (Hz) is the SI unit of frequency, equal to one cycle per second.
Q26. [+1, -0.25]Science
Which plant hormone promotes growth?
A. Auxin
B. Gibberellin
C. Cytokinin
D. Ethylene
Correct Answer: A Auxin is a plant hormone that regulates cell elongation, phototropism, and growth.
Q27. [+1, -0.25]Science
What is the chemical formula of ammonia?
A. NH3
B. NH4
C. N2H4
D. NO2
Correct Answer: A Ammonia (NH3) is a colourless gas with a pungent odour, composed of nitrogen and hydrogen.
Q28. [+1, -0.25]Science
How many chambers does the human heart have?
A. 2
B. 3
C. 4
D. 5
Correct Answer: C The human heart has four chambers: two atria and two ventricles.
Q29. [+1, -0.25]Science
What type of bond holds the two oxygen atoms together in an O2 molecule?
A. Ionic bond
B. Covalent bond
C. Metallic bond
D. Hydrogen bond
Correct Answer: B Two oxygen atoms share two pairs of electrons forming a double covalent bond in O2.
Q30. [+1, -0.25]Science
Which property of sound determines its pitch?
A. Amplitude
B. Frequency
C. Speed
D. Wavelength
Correct Answer: B Pitch depends on the frequency of sound waves – higher frequency gives a higher pitch.
Q31. [+1, -0.25]Science
Which element has the highest electronegativity?
A. Chlorine
B. Fluorine
C. Oxygen
D. Nitrogen
Correct Answer: B Fluorine (3.98 on the Pauling scale) is the most electronegative element.
Q32. [+1, -0.25]Science
Which part of the flower produces pollen?
A. Stamen
B. Pistil
C. Sepal
D. Petal
Correct Answer: A The stamen is the male reproductive part of a flower containing the anther, which produces pollen.
Q33. [+1, -0.25]Science
A concave mirror is also called a:
A. Diverging mirror
B. Converging mirror
C. Plane mirror
D. Flat mirror
Correct Answer: B A concave mirror converges parallel light rays to a single focal point.
Q34. [+1, -0.25]Science
What is the chemical formula of sodium hydroxide?
A. NaOH
B. Na2O
C. Na2CO3
D. NaCl
Correct Answer: A Sodium hydroxide (NaOH) is a strong base also known as caustic soda.
Q35. [+1, -0.25]Science
What is the function of the pancreas?
A. Filter blood
B. Produce insulin and digestive enzymes
C. Store bile
D. Pump blood
Correct Answer: B The pancreas produces insulin (regulates blood sugar) and pancreatic enzymes for digestion.
Q36. [+1, -0.25]Science
The kinetic energy of an object is given by the formula:
A. mgh
B. ½mv²
C. mv
D. ½mv
Correct Answer: B Kinetic energy = ½mv², where m is mass and v is velocity.
Q37. [+1, -0.25]Science
Which element is represented by the symbol ‘K’?
A. Krypton
B. Potassium
C. Kryptonite
D. Kurchatovium
Correct Answer: B K is the symbol for Potassium, from the Latin ‘Kalium’.
Q38. [+1, -0.25]Science
Which vitamin deficiency causes scurvy?
A. Vitamin A
B. Vitamin B1
C. Vitamin C
D. Vitamin D
Correct Answer: C Scurvy is caused by a deficiency of Vitamin C (ascorbic acid), leading to bleeding gums and weakness.
Q39. [+1, -0.25]Science
Which blood vessel carries blood away from the heart?
A. Artery
B. Vein
C. Capillary
D. Venule
Correct Answer: A Arteries carry oxygenated blood away from the heart to the body (except the pulmonary artery).
Q40. [+1, -0.25]Science
What is the chemical formula of calcium carbonate?
A. CaO
B. Ca(OH)2
C. CaCO3
D. CaCl2
Correct Answer: C Calcium carbonate (CaCO3) is the main component of limestone, chalk, and marble.
Q41. [+1, -0.25]Science
The phenomenon of splitting of white light into its component colours is called:
A. Reflection
B. Refraction
C. Dispersion
D. Diffraction
Correct Answer: C Dispersion is the separation of white light into its constituent colours, as seen in a rainbow.
Q42. [+1, -0.25]Science
Which gas is produced during photosynthesis?
A. Oxygen
B. Carbon dioxide
C. Nitrogen
D. Hydrogen
Correct Answer: A During photosynthesis, plants release oxygen as a by-product while converting CO2 and water into glucose.
Q43. [+1, -0.25]Science
What is the SI unit of temperature?
A. Celsius
B. Kelvin
C. Fahrenheit
D. Joule
Correct Answer: B The Kelvin (K) is the SI base unit of thermodynamic temperature.
Q44. [+1, -0.25]Science
What is the largest ecosystem on Earth?
A. Ocean
B. Forest
C. Desert
D. Grassland
Correct Answer: A The ocean covers about 71% of Earth’s surface and is the largest aquatic ecosystem.
Q45. [+1, -0.25]Science
Which element has atomic number 1?
A. Hydrogen
B. Helium
C. Lithium
D. Beryllium
Correct Answer: A Hydrogen is the lightest element with atomic number 1, consisting of 1 proton and 1 electron.
Q46. [+1, -0.25]Science
The process of heat transfer through actual movement of particles is called:
A. Conduction
B. Convection
C. Radiation
D. Evaporation
Correct Answer: B Convection transfers heat through the bulk movement of molecules within fluids (liquids and gases).
Q47. [+1, -0.25]Science
Which element is represented by the symbol ‘Na’?
A. Neon
B. Sodium
C. Nickel
D. Niobium
Correct Answer: B Na is the symbol for Sodium, derived from Latin ‘Natrium’.
Q48. [+1, -0.25]Science
Which animal is known as the ‘Ship of the Desert’?
A. Horse
B. Camel
C. Donkey
D. Llama
Correct Answer: B Camels are well-adapted to desert life and have been used for transport, earning the nickname ‘Ship of the Desert’.
Q49. [+1, -0.25]Science
Newton’s second law of motion gives the relation between:
A. Force, mass, and acceleration
B. Force and displacement
C. Energy and work
D. Pressure and volume
Correct Answer: A Newton’s second law states F = ma, establishing the relationship between force, mass, and acceleration.
Q50. [+1, -0.25]Science
What is the chemical formula of ethanol?
A. CH3OH
B. C2H5OH
C. C3H7OH
D. C2H4
Correct Answer: B Ethanol (ethyl alcohol) has the formula C2H5OH, used as a solvent and fuel additive.
Q51. [+1, -0.25]Science
What is the structural and functional unit of the kidney called?
A. Neuron
B. Nephron
C. Alveolus
D. Villus
Correct Answer: B Each kidney contains about one million nephrons that filter blood to produce urine.
Q52. [+1, -0.25]Science
Which mirror is used by dentists to examine teeth?
A. Concave mirror
B. Convex mirror
C. Plane mirror
D. Parabolic mirror
Correct Answer: A Dentists use concave mirrors to obtain an enlarged, upright image of the teeth.
Q53. [+1, -0.25]Science
What is the pH range of bases?
A. 0 to 6
B. 7
C. 8 to 14
D. 0 to 14
Correct Answer: C Bases have a pH greater than 7, with strong bases reaching up to pH 14.
Q54. [+1, -0.25]Science
The process of cell division that results in two identical daughter cells is called:
A. Mitosis
B. Meiosis
C. Binary fission
D. Budding
Correct Answer: A Mitosis produces two genetically identical diploid daughter cells for growth and repair.
Q55. [+1, -0.25]Science
Which gas is the main constituent of the Sun?
A. Hydrogen
B. Helium
C. Carbon
D. Oxygen
Correct Answer: A The Sun is about 73% hydrogen and 25% helium by mass, with fusion powering it.
Q56. [+1, -0.25]Science
What type of reaction is the burning of wood?
A. Endothermic
B. Combustion
C. Neutralisation
D. Decomposition
Correct Answer: B Burning is a combustion reaction where a substance reacts rapidly with oxygen, releasing heat and light.
Q57. [+1, -0.25]Science
Rusting of iron is an example of which process?
A. Reduction
B. Oxidation
C. Sublimation
D. Evaporation
Correct Answer: B Rusting is the oxidation of iron in the presence of oxygen and water to form hydrated iron(III) oxide.
Q58. [+1, -0.25]Science
Which part of the brain controls voluntary actions like thinking and movement?
A. Cerebrum
B. Cerebellum
C. Medulla oblongata
D. Hypothalamus
Correct Answer: A The cerebrum is the largest part of the brain, responsible for voluntary movement, thought, and sensory processing.
Q59. [+1, -0.25]Science
Which planet is closest to the Sun?
A. Mercury
B. Venus
C. Earth
D. Mars
Correct Answer: A Mercury is the closest planet to the Sun, at an average distance of about 57.9 million km.
Q60. [+1, -0.25]Science
Which element is represented by the symbol ‘Ca’?
A. Calcium
B. Carbon
C. Cadmium
D. Californium
Correct Answer: A Ca is the chemical symbol for Calcium, an essential mineral for bones and teeth.
Q61. [+1, -0.25]Science
Which vitamin is also known as ascorbic acid?
A. Vitamin A
B. Vitamin B2
C. Vitamin C
D. Vitamin E
Correct Answer: C Ascorbic acid is the chemical name for Vitamin C, an essential nutrient and antioxidant.
Q62. [+1, -0.25]Science
What is the unit of electric charge?
A. Volt
B. Coulomb
C. Ampere
D. Ohm
Correct Answer: B The Coulomb (C) is the SI unit of electric charge, equal to the charge of about 6.24 x 10^18 electrons.
Q63. [+1, -0.25]Science
Which disease is caused by the protozoan Plasmodium?
A. Typhoid
B. Malaria
C. Dengue
D. Cholera
Correct Answer: B Malaria is caused by the Plasmodium parasite, transmitted through the bite of infected female Anopheles mosquitoes.
Q64. [+1, -0.25]Science
The phenomenon of change in frequency of waves due to relative motion is called the:
A. Photoelectric effect
B. Doppler effect
C. Compton effect
D. Raman effect
Correct Answer: B The Doppler effect describes the change in frequency or wavelength of waves relative to an observer.
Q65. [+1, -0.25]Science
Which element is the most abundant in the Earth’s crust?
A. Oxygen
B. Silicon
C. Aluminium
D. Iron
Correct Answer: A Oxygen makes up about 46.6% of the Earth’s crust by mass, followed by silicon at 27.7%.
Q66. [+1, -0.25]Science
What type of animal eats both plants and animals?
A. Herbivore
B. Carnivore
C. Omnivore
D. Decomposer
Correct Answer: C Omnivores, such as humans and bears, consume both plant and animal matter.
Q67. [+1, -0.25]Science
What is the chemical symbol for silver?
A. Si
B. Ag
C. Au
D. Pb
Correct Answer: B Ag is the symbol for silver, from the Latin word ‘Argentum’.
Q68. [+1, -0.25]Science
Which gland is called the ‘master gland’ of the body?
A. Thyroid
B. Pituitary
C. Adrenal
D. Pineal
Correct Answer: B The pituitary gland controls the functions of other endocrine glands and is called the master gland.
Q69. [+1, -0.25]Science
The work done when force is applied at right angles to displacement is:
A. Maximum
B. Zero
C. Negative
D. Infinite
Correct Answer: B Work = Fd cosθ. When θ = 90°, cosθ = 0, so work = 0.
Q70. [+1, -0.25]Science
What is the chemical symbol for lead?
A. Ld
B. Le
C. Pb
D. Pl
Correct Answer: C Pb is the symbol for lead, from the Latin word ‘Plumbum’.
Q71. [+1, -0.25]Science
What is the largest mammal on Earth?
A. Blue whale
B. African elephant
C. Giraffe
D. Hippopotamus
Correct Answer: A The blue whale is the largest mammal, reaching up to 30 metres in length and 200 tons.
Q72. [+1, -0.25]Science
Which type of lens is used to correct hypermetropia (farsightedness)?
A. Convex lens
B. Concave lens
C. Bifocal lens
D. Cylindrical lens
Correct Answer: A Hypermetropia is corrected using a convex (converging) lens that focuses light onto the retina.
Q73. [+1, -0.25]Science
What is the chemical formula of carbon dioxide?
A. CO2
B. CO
C. C2O
D. CO3
Correct Answer: A Carbon dioxide (CO2) is a colourless gas produced by respiration and combustion.
Q74. [+1, -0.25]Science
The study of fungi is called:
A. Botany
B. Zoology
C. Mycology
D. Virology
Correct Answer: C Mycology is the branch of biology concerned with the study of fungi.
Q75. [+1, -0.25]Science
What is the unit of magnetic field strength in the SI system?
A. Gauss
B. Tesla
C. Weber
D. Henry
Correct Answer: B The Tesla (T) is the SI unit of magnetic flux density or magnetic field strength.
Q76. [+1, -0.25]Science
Which vitamin is known as retinol?
A. Vitamin A
B. Vitamin B1
C. Vitamin C
D. Vitamin D
Correct Answer: A Retinol is the animal form of Vitamin A, essential for vision and immune function.
Q77. [+1, -0.25]Science
Which planet is known as the ‘Morning Star’ or ‘Evening Star’?
A. Venus
B. Mars
C. Jupiter
D. Mercury
Correct Answer: A Venus is the brightest planet visible from Earth and appears in the morning or evening sky.
Q78. [+1, -0.25]Science
What is the function of ribosomes in a cell?
A. Energy production
B. Protein synthesis
C. Lipid synthesis
D. DNA replication
Correct Answer: B Ribosomes are the site of protein synthesis, translating mRNA into polypeptide chains.
Q79. [+1, -0.25]Science
Which part of the electromagnetic spectrum has the longest wavelength?
A. X-rays
B. Ultraviolet
C. Infrared
D. Radio waves
Correct Answer: D Radio waves have the longest wavelengths in the EM spectrum, ranging from millimetres to kilometres.
Q80. [+1, -0.25]Science
What is the name of our galaxy?
A. Andromeda
B. Milky Way
C. Triangulum
D. Sombrero
Correct Answer: B The Milky Way is the spiral galaxy that contains our solar system.
Q81. [+1, -0.25]Science
Which metal is the best conductor of electricity?
A. Copper
B. Silver
C. Gold
D. Aluminium
Correct Answer: B Silver has the highest electrical conductivity of any metal at room temperature.
Q82. [+1, -0.25]Science
Which gas do plants absorb from the atmosphere during photosynthesis?
A. Carbon dioxide
B. Oxygen
C. Nitrogen
D. Hydrogen
Correct Answer: A Plants absorb carbon dioxide through stomata and use it to synthesise glucose during photosynthesis.
Q83. [+1, -0.25]Science
The atomic number of carbon is:
A. 4
B. 6
C. 8
D. 12
Correct Answer: B Carbon has atomic number 6, meaning it has 6 protons and typically 6 neutrons (carbon-12).
Q84. [+1, -0.25]Science
What is the SI unit of energy?
A. Watt
B. Joule
C. Newton
D. Pascal
Correct Answer: B The Joule (J) is the SI unit of energy, equal to the work done by a force of one newton over one metre.
Q85. [+1, -0.25]Science
Which blood vessel carries deoxygenated blood from the heart to the lungs?
A. Pulmonary artery
B. Pulmonary vein
C. Aorta
D. Vena cava
Correct Answer: A The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs for oxygenation.
Q86. [+1, -0.25]Science
A body moving in a uniform circular motion experiences which type of acceleration?
A. Centripetal acceleration
B. Tangential acceleration
C. Linear acceleration
D. Angular acceleration
Correct Answer: A In uniform circular motion, centripetal acceleration acts towards the centre of the circle.
Q87. [+1, -0.25]Science
What is the chemical symbol for zinc?
A. Zn
B. Zc
C. Zi
D. Zr
Correct Answer: A Zn is the chemical symbol for zinc, a bluish-white metal used in galvanisation.
Q88. [+1, -0.25]Science
What is the speed of sound in air at room temperature approximately?
A. 300 m/s
B. 343 m/s
C. 500 m/s
D. 700 m/s
Correct Answer: B The speed of sound in air at 20°C is approximately 343 metres per second.
Q89. [+1, -0.25]Science
Which element has the chemical symbol ‘Cl’?
A. Calcium
B. Carbon
C. Chlorine
D. Chromium
Correct Answer: C Cl is the chemical symbol for Chlorine, a greenish-yellow halogen gas.
Q90. [+1, -0.25]Science
Which planet has the most prominent ring system?
A. Saturn
B. Jupiter
C. Uranus
D. Neptune
Correct Answer: A Saturn’s ring system is the largest and most visible in the solar system, composed of ice and rock particles.
Q91. [+1, -0.25]Science
Which scientist proposed the theory of relativity?
A. Isaac Newton
B. Albert Einstein
C. Galileo Galilei
D. Niels Bohr
Correct Answer: B Albert Einstein proposed the special theory of relativity (1905) and the general theory of relativity (1915).
Q92. [+1, -0.25]Science
What is the chemical symbol for magnesium?
A. Mn
B. Mg
C. Ma
D. Md
Correct Answer: B Mg is the chemical symbol for magnesium, a light alkaline earth metal.
Q93. [+1, -0.25]Science
How many planets are in our solar system?
A. 7
B. 8
C. 9
D. 10
Correct Answer: B There are 8 planets in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
Q94. [+1, -0.25]Science
What is the chemical formula of hydrochloric acid?
A. HCl
B. H2SO4
C. HNO3
D. H2CO3
Correct Answer: A Hydrochloric acid (HCl) is a strong acid found naturally in gastric juice.
Q95. [+1, -0.25]Science
What type of energy is stored in a stretched spring?
A. Kinetic energy
B. Chemical energy
C. Elastic potential energy
D. Thermal energy
Correct Answer: C A stretched spring stores elastic potential energy due to its deformation from the equilibrium position.
Q96. [+1, -0.25]Science
Which vitamin is known as niacin?
A. Vitamin B1
B. Vitamin B2
C. Vitamin B3
D. Vitamin B6
Correct Answer: C Niacin is Vitamin B3, which helps convert food into energy and supports skin and nerve health.
Q97. [+1, -0.25]Science
The law of conservation of momentum states that:
A. Momentum is always zero
B. Total momentum before collision equals total momentum after collision
C. Momentum increases with time
D. Momentum decreases with friction
Correct Answer: B In an isolated system, the total momentum before and after a collision remains constant.
Q98. [+1, -0.25]Science
Which element is essential for the formation of haemoglobin?
A. Calcium
B. Iron
C. Iodine
D. Potassium
Correct Answer: B Iron is a key component of haemoglobin, the protein in red blood cells that carries oxygen.
Q99. [+1, -0.25]Science
Which lens is used in a magnifying glass?
A. Convex lens
B. Concave lens
C. Plano-concave lens
D. Bifocal lens
Correct Answer: A A magnifying glass uses a convex lens to produce an enlarged virtual image of an object.
Q100. [+1, -0.25]Science
The phenomenon of the Moon’s changing appearance over a month is caused by:
A. Earth’s shadow
B. Revolution of the Moon around Earth
C. Rotation of the Moon
D. Clouds blocking sunlight
Correct Answer: B The phases of the Moon occur because we see different portions of the Moon’s lit half as it orbits Earth.