500+ Everyday Science MCQs

Everyday Science MCQs (500 Questions)

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1. What is the primary source of energy for Earth's climate system?

• A) Geothermal energy
• B) Sun
• C) Moon
• D) Earth's core

Correct Answer: B) Sun

2. Which blood cells are responsible for fighting infections?

• A) Red blood cells
• B) White blood cells
• C) Platelets
• D) Plasma

Correct Answer: B) White blood cells

3. What gas turns lime water milky?

• A) Oxygen
• B) Nitrogen
• C) Carbon dioxide
• D) Hydrogen

Correct Answer: C) Carbon dioxide

4. Which vitamin is also known as ascorbic acid?

• A) Vitamin A
• B) Vitamin B
• C) Vitamin C
• D) Vitamin D

Correct Answer: C) Vitamin C

5. The SI unit of force is:

• A) Joule
• B) Newton
• C) Watt
• D) Pascal

Correct Answer: B) Newton

6. Which planet has the most moons?

• A) Jupiter
• B) Saturn
• C) Uranus
• D) Neptune

Correct Answer: B) Saturn

7. The hardest natural substance known is:

• A) Gold
• B) Iron
• C) Diamond
• D) Platinum

Correct Answer: C) Diamond

8. Which part of the eye controls the amount of light entering?

• A) Retina
• B) Iris
• C) Cornea
• D) Lens

Correct Answer: B) Iris

9. What is the chemical name of baking soda?

• A) Sodium chloride
• B) Sodium bicarbonate
• C) Calcium carbonate
• D) Sodium hydroxide

Correct Answer: B) Sodium bicarbonate

10. Which gas is used in balloons to make them float?

• A) Oxygen
• B) Hydrogen
• C) Helium
• D) Nitrogen

Correct Answer: C) Helium

11. The process of conversion of sugar into alcohol is called:

• A) Oxidation
• B) Fermentation
• C) Reduction
• D) Distillation

Correct Answer: B) Fermentation

12. Which metal is liquid at room temperature?

• A) Iron
• B) Mercury
• C) Gold
• D) Silver

Correct Answer: B) Mercury

13. The powerhouse of the cell is:

• A) Nucleus
• B) Mitochondria
• C) Ribosome
• D) Golgi body

Correct Answer: B) Mitochondria

14. Sound cannot travel through:

• A) Air
• B) Water
• C) Vacuum
• D) Steel

Correct Answer: C) Vacuum

15. Which acid is present in lemon?

• A) Acetic acid
• B) Citric acid
• C) Tartaric acid
• D) Lactic acid

Correct Answer: B) Citric acid

50. Which is the longest bone in the human body?

• A) Humerus
• B) Femur
• C) Tibia
• D) Radius

Correct Answer: B) Femur

51. The SI unit of power is:

• A) Joule
• B) Watt
• C) Newton
• D) Pascal

Correct Answer: B) Watt

52. Which vitamin deficiency causes scurvy?

• A) Vitamin A
• B) Vitamin B1
• C) Vitamin C
• D) Vitamin D

Correct Answer: C) Vitamin C

53. The Earth's ozone layer is found in which atmospheric layer?

• A) Troposphere
• B) Stratosphere
• C) Mesosphere
• D) Thermosphere

Correct Answer: B) Stratosphere

54. Which metal is used in thermometers due to its high coefficient of expansion?

• A) Copper
• B) Mercury
• C) Aluminum
• D) Iron

Correct Answer: B) Mercury

55. The unit of frequency is:

• A) Hertz
• B) Decibel
• C) Lux
• D) Tesla

Correct Answer: A) Hertz

56. Which hormone regulates blood sugar levels?

• A) Adrenaline
• B) Insulin
• C) Thyroxine
• D) Estrogen

Correct Answer: B) Insulin

57. The speed of light in vacuum is approximately:

• A) 3 × 10^6 m/s
• B) 3 × 10^8 m/s
• C) 3 × 10^10 m/s
• D) 3 × 10^12 m/s

Correct Answer: B) 3 × 10^8 m/s

58. Which gas is known as laughing gas?

• A) Carbon monoxide
• B) Nitrous oxide
• C) Sulfur dioxide
• D) Methane

Correct Answer: B) Nitrous oxide

59. The largest gland in the human body is:

• A) Pancreas
• B) Liver
• C) Thyroid
• D) Pituitary

Correct Answer: B) Liver

60. What causes the rusting of iron?

• A) Oxidation
• B) Reduction
• C) Sublimation
• D) Evaporation

Correct Answer: A) Oxidation

61. Which planet is closest to the Sun?

• A) Venus
• B) Mercury
• C) Earth
• D) Mars

Correct Answer: B) Mercury

62. The pH value of human blood is approximately:

• A) 4.5
• B) 7.4
• C) 8.5
• D) 10.0

Correct Answer: B) 7.4

63. Which instrument measures atmospheric pressure?

• A) Thermometer
• B) Barometer
• C) Hygrometer
• D) Anemometer

Correct Answer: B) Barometer

64. The main constituent of natural gas is:

• A) Butane
• B) Methane
• C) Propane
• D) Ethane

Correct Answer: B) Methane

65. Which part of the brain controls balance and posture?

• A) Cerebrum
• B) Cerebellum
• C) Medulla
• D) Hypothalamus

Correct Answer: B) Cerebellum

66. The process of splitting water molecules using light energy is called:

• A) Photolysis
• B) Hydrolysis
• C) Electrolysis
• D) Thermolysis

Correct Answer: A) Photolysis

67. Which element has the atomic number 1?

• A) Helium
• B) Hydrogen
• C) Lithium
• D) Carbon

Correct Answer: B) Hydrogen

68. The deficiency of iodine causes:

• A) Goiter
• B) Anemia
• C) Rickets
• D) Scurvy

Correct Answer: A) Goiter

69. Which is the only planet that rotates clockwise?

• A) Mars
• B) Venus
• C) Jupiter
• D) Uranus

Correct Answer: B) Venus

70. The chemical formula of water is:

• A) CO2
• B) H2O
• C) NaCl
• D) O2

Correct Answer: B) H2O

71. Which blood group is known as the universal donor?

• A) A+
• B) B-
• C) AB+
• D) O-

Correct Answer: D) O-

72. The SI unit of energy is:

• A) Newton
• B) Joule
• C) Watt
• D) Ampere

Correct Answer: B) Joule

73. Which gas is used in fire extinguishers?

• A) Oxygen
• B) Carbon dioxide
• C) Nitrogen
• D) Hydrogen

Correct Answer: B) Carbon dioxide

74. The human eye forms the image of an object at its:

• A) Cornea
• B) Iris
• C) Retina
• D) Lens

Correct Answer: C) Retina

75. Which is the lightest metal?

• A) Sodium
• B) Lithium
• C) Potassium
• D) Magnesium

Correct Answer: B) Lithium

76. The main source of vitamin D is:

• A) Green vegetables
• B) Sunlight
• C) Milk
• D) Fish

Correct Answer: B) Sunlight

77. Which law states that action and reaction are equal and opposite?

• A) Newton's First Law
• B) Newton's Second Law
• C) Newton's Third Law
• D) Law of Gravitation

Correct Answer: C) Newton's Third Law

78. The chemical name of table salt is:

• A) Sodium bicarbonate
• B) Sodium chloride
• C) Calcium carbonate
• D) Sodium hydroxide

Correct Answer: B) Sodium chloride

79. Which organ filters blood in the human body?

• A) Liver
• B) Kidney
• C) Lungs
• D) Heart

Correct Answer: B) Kidney

80. The study of earthquakes is called:

• A) Meteorology
• B) Seismology
• C) Geology
• D) Oceanography

Correct Answer: B) Seismology

81. Which gas is essential for photosynthesis?

• A) Oxygen
• B) Carbon dioxide
• C) Nitrogen
• D) Hydrogen

Correct Answer: B) Carbon dioxide

82. The human skeleton has how many bones at birth?

• A) 206
• B) 270
• C) 300
• D) 350

Correct Answer: B) 270

83. Which is the most abundant gas in the universe?

• A) Oxygen
• B) Hydrogen
• C) Nitrogen
• D) Helium

Correct Answer: B) Hydrogen

84. The device used to measure electric current is:

• A) Voltmeter
• B) Ammeter
• C) Galvanometer
• D) Ohmmeter

Correct Answer: B) Ammeter

85. Which acid is found in vinegar?

• A) Citric acid
• B) Acetic acid
• C) Lactic acid
• D) Tartaric acid

Correct Answer: B) Acetic acid

86. The Moon is a:

• A) Planet
• B) Star
• C) Satellite
• D) Comet

Correct Answer: C) Satellite

87. Which vitamin helps in blood clotting?

• A) Vitamin A
• B) Vitamin K
• C) Vitamin E
• D) Vitamin B

Correct Answer: B) Vitamin K

88. The boiling point of water decreases when:

• A) Pressure increases
• B) Pressure decreases
• C) Temperature increases
• D) Altitude decreases

Correct Answer: B) Pressure decreases

89. Which is the smallest unit of life?

• A) Tissue
• B) Cell
• C) Organ
• D) System

Correct Answer: B) Cell

90. The color of the sky appears blue due to:

• A) Reflection
• B) Refraction
• C) Scattering
• D) Dispersion

Correct Answer: C) Scattering

91. Which gas turns lime water milky?

• A) Oxygen
• B) Nitrogen
• C) Carbon dioxide
• D) Hydrogen

Correct Answer: C) Carbon dioxide

92. The powerhouse of the cell is:

• A) Nucleus
• B) Mitochondria
• C) Ribosome
• D) Endoplasmic reticulum

Correct Answer: B) Mitochondria

93. Which is the hardest substance found in nature?

• A) Gold
• B) Iron
• C) Diamond
• D) Platinum

Correct Answer: C) Diamond

94. The primary source of energy for Earth's climate is:

• A) Geothermal
• B) Solar
• C) Nuclear
• D) Tidal

Correct Answer: B) Solar

95. Which vitamin is essential for vision?

• A) Vitamin B
• B) Vitamin A
• C) Vitamin C
• D) Vitamin D

Correct Answer: B) Vitamin A

96. The process by which plants lose water vapor is called:

• A) Photosynthesis
• B) Transpiration
• C) Respiration
• D) Germination

Correct Answer: B) Transpiration

97. Which element is diamond made of?

• A) Silicon
• B) Carbon
• C) Sulfur
• D) Nitrogen

Correct Answer: B) Carbon

98. The normal body temperature of a human is:

• A) 35°C
• B) 37°C
• C) 39°C
• D) 42°C

Correct Answer: B) 37°C

99. Which gas do plants release during photosynthesis?

• A) Carbon dioxide
• B) Oxygen
• C) Nitrogen
• D) Hydrogen

Correct Answer: B) Oxygen

100. The longest bone in the human body is:

• A) Humerus
• B) Femur
• C) Tibia
• D) Fibula

Correct Answer: B) Femur

101. Which is the most abundant element in the Earth's crust?

• A) Iron
• B) Oxygen
• C) Silicon
• D) Aluminum

Correct Answer: B) Oxygen

102. The instrument used to measure humidity is called:

• A) Barometer
• B) Hygrometer
• C) Anemometer
• D) Thermometer

Correct Answer: B) Hygrometer

103. Which vitamin is also known as retinol?

• A) Vitamin A
• B) Vitamin B
• C) Vitamin C
• D) Vitamin K

Correct Answer: A) Vitamin A

104. The chemical formula for common salt is:

• A) NaHCO3
• B) NaCl
• C) CaCO3
• D) KCl

Correct Answer: B) NaCl

105. Which planet is known as the Evening Star?

• A) Mars
• B) Venus
• C) Jupiter
• D) Mercury

Correct Answer: B) Venus

106. The deficiency of Vitamin D causes:

• A) Beriberi
• B) Rickets
• C) Scurvy
• D) Night blindness

Correct Answer: B) Rickets

107. Which gas is used in electric bulbs to prevent filament from oxidizing?

• A) Oxygen
• B) Nitrogen
• C) Argon
• D) Helium

Correct Answer: C) Argon

108. The main function of the kidneys is to:

• A) Produce insulin
• B) Filter blood
• C) Pump blood
• D) Digest food

Correct Answer: B) Filter blood

109. What is the unit of electrical resistance?

• A) Ampere
• B) Volt
• C) Ohm
• D) Watt

Correct Answer: C) Ohm

110. Which is the smallest planet in our solar system?

• A) Mars
• B) Mercury
• C) Venus
• D) Pluto (dwarf)

Correct Answer: B) Mercury

111. The process of conversion of solid directly into gas is called:

• A) Condensation
• B) Sublimation
• C) Evaporation
• D) Fusion

Correct Answer: B) Sublimation

112. Which blood group is known as the universal recipient?

• A) A+
• B) B-
• C) AB+
• D) O-

Correct Answer: C) AB+

113. The green pigment in plants is called:

• A) Hemoglobin
• B) Chlorophyll
• C) Melanin
• D) Carotene

Correct Answer: B) Chlorophyll

114. Which acid is present in the human stomach?

• A) Citric acid
• B) Hydrochloric acid
• C) Sulfuric acid
• D) Acetic acid

Correct Answer: B) Hydrochloric acid

115. The SI unit of pressure is:

• A) Pascal
• B) Newton
• C) Joule
• D) Watt

Correct Answer: A) Pascal

116. Which organ produces bile?

• A) Pancreas
• B) Liver
• C) Gallbladder
• D) Spleen

Correct Answer: B) Liver

117. The speed of sound in air is approximately:

• A) 330 m/s
• B) 1500 m/s
• C) 300,000 km/s
• D) 3 × 10^8 m/s

Correct Answer: A) 330 m/s

118. Which element is represented by the symbol 'Fe'?

• A) Fluorine
• B) Iron
• C) Francium
• D) Fermium

Correct Answer: B) Iron

119. The human heart has how many chambers?

• A) 2
• B) 3
• C) 4
• D) 5

Correct Answer: C) 4

120. Which gas causes global warming?

• A) Oxygen
• B) Nitrogen
• C) Carbon dioxide
• D) Argon

Correct Answer: C) Carbon dioxide

121. The study of fossils is called:

• A) Paleontology
• B) Anthropology
• C) Geology
• D) Botany

Correct Answer: A) Paleontology

122. Which is the main source of protein?

• A) Rice
• B) Meat and pulses
• C) Fruits
• D) Vegetables

Correct Answer: B) Meat and pulses

123. The chemical name of washing soda is:

• A) Sodium bicarbonate
• B) Sodium carbonate
• C) Calcium carbonate
• D) Sodium hydroxide

Correct Answer: B) Sodium carbonate

124. Which layer of the atmosphere protects us from harmful UV rays?

• A) Troposphere
• B) Stratosphere
• C) Mesosphere
• D) Exosphere

Correct Answer: B) Stratosphere

125. The normal pH of human blood is:

• A) 6.4
• B) 7.4
• C) 8.4
• D) 9.4

Correct Answer: B) 7.4

126. Which metal is used to make airplanes?

• A) Iron
• B) Aluminum
• C) Copper
• D) Gold

Correct Answer: B) Aluminum

127. The unit of luminous intensity is:

• A) Candela
• B) Lux
• C) Lumen
• D) Kelvin

Correct Answer: A) Candela

128. Which hormone is known as the stress hormone?

• A) Insulin
• B) Cortisol
• C) Thyroxine
• D) Adrenaline

Correct Answer: B) Cortisol

129. The boiling point of water on mountains is:

• A) Higher
• B) Lower
• C) Same
• D) Zero

Correct Answer: B) Lower

130. Which is the largest gland in the human body?

• A) Thyroid
• B) Liver
• C) Pancreas
• D) Pituitary

Correct Answer: B) Liver

131. The chemical symbol for silver is:

• A) Ag
• B) Au
• C) Si
• D) Sr

Correct Answer: A) Ag

132. Which part of the plant conducts water?

• A) Phloem
• B) Xylem
• C) Stomata
• D) Root hair

Correct Answer: B) Xylem

133. The main source of Vitamin C is:

• A) Milk
• B) Citrus fruits
• C) Eggs
• D) Meat

Correct Answer: B) Citrus fruits

134. Which law is also known as the law of inertia?

• A) Newton's First Law
• B) Newton's Second Law
• C) Newton's Third Law
• D) Law of Gravitation

Correct Answer: A) Newton's First Law

135. The human brain is protected by:

• A) Skull
• B) Ribs
• C) Spine
• D) Pelvis

Correct Answer: A) Skull

136. Which gas is filled in fluorescent tubes?

• A) Neon
• B) Argon
• C) Mercury vapor
• D) Helium

Correct Answer: C) Mercury vapor

137. The number of bones in an adult human body is:

• A) 206
• B) 270
• C) 300
• D) 350

Correct Answer: A) 206

138. Which is the fastest land animal?

• A) Lion
• B) Cheetah
• C) Horse
• D) Leopard

Correct Answer: B) Cheetah

139. The chemical formula of ozone is:

• A) O2
• B) O3
• C) CO2
• D) N2

Correct Answer: B) O3

140. Which vitamin prevents beriberi?

• A) Vitamin B1
• B) Vitamin B12
• C) Vitamin C
• D) Vitamin D

Correct Answer: A) Vitamin B1

141. The device that converts sound into electrical signals is:

• A) Speaker
• B) Microphone
• C) Amplifier
• D) Radio

Correct Answer: B) Microphone

142. Which is the main gas in Earth's atmosphere?

• A) Oxygen
• B) Nitrogen
• C) Carbon dioxide
• D) Argon

Correct Answer: B) Nitrogen

143. The study of weather is called:

• A) Meteorology
• B) Astronomy
• C) Geology
• D) Biology

Correct Answer: A) Meteorology

144. Which metal is a poor conductor of electricity?

• A) Copper
• B) Silver
• C) Lead
• D) Gold

Correct Answer: C) Lead

145. The human eye lens is:

• A) Convex
• B) Concave
• C) Plane
• D) Bifocal

Correct Answer: A) Convex

146. Which is the lightest gas?

• A) Hydrogen
• B) Helium
• C) Oxygen
• D) Nitrogen

Correct Answer: A) Hydrogen

147. The main component of biogas is:

• A) Carbon dioxide
• B) Methane
• C) Oxygen
• D) Nitrogen

Correct Answer: B) Methane

148. Which disease is caused by deficiency of Vitamin B12?

• A) Pernicious anemia
• B) Scurvy
• C) Rickets
• D) Goiter

Correct Answer: A) Pernicious anemia

149. The unit of wavelength is:

• A) Hertz
• B) Meter
• C) Second
• D) Joule

Correct Answer: B) Meter

150. Which is the only bird that can fly backwards?

• A) Eagle
• B) Hummingbird
• C) Sparrow
• D) Ostrich

Correct Answer: B) Hummingbird

151. Pedology is the scientific study of:

• A) Birds
• B) Languages
• C) Soils
• D) Ancient rocks

Correct Answer: C) Soils

152. The SI unit of luminous flux is:

• A) Lux
• B) Lumen
• C) Candela
• D) Watt

Correct Answer: B) Lumen

153. Which gas is primarily responsible for the greenhouse effect on Earth?

• A) Oxygen
• B) Nitrogen
• C) Carbon dioxide
• D) Argon

Correct Answer: C) Carbon dioxide

154. The deficiency of which vitamin leads to night blindness?

• A) Vitamin B1
• B) Vitamin A
• C) Vitamin C
• D) Vitamin K

Correct Answer: B) Vitamin A

155. Which is the study of fossils?

• A) Paleontology
• B) Meteorology
• C) Seismology
• D) Oceanography

Correct Answer: A) Paleontology

156. The chemical formula for bleaching powder is:

• A) CaOCl₂
• B) NaHCO₃
• C) Na₂CO₃
• D) CaCO₃

Correct Answer: A) CaOCl₂

157. Which part of the human eye is responsible for color vision?

• A) Cornea
• B) Iris
• C) Cones in retina
• D) Lens

Correct Answer: C) Cones in retina

158. The freezing point of seawater is lower than fresh water due to:

• A) Higher density
• B) Dissolved salts
• C) Lower pressure
• D) Higher altitude

Correct Answer: B) Dissolved salts

159. Which hormone is secreted by the pancreas to lower blood sugar?

• A) Glucagon
• B) Insulin
• C) Adrenaline
• D) Thyroxine

Correct Answer: B) Insulin

160. The branch of science dealing with very low temperatures is:

• A) Cryogenics
• B) Thermodynamics
• C) Kinetics
• D) Acoustics

Correct Answer: A) Cryogenics

161. Which element is the most abundant in the human body?

• A) Carbon
• B) Oxygen
• C) Hydrogen
• D) Nitrogen

Correct Answer: B) Oxygen

162. The device that measures wind speed is called:

• A) Barometer
• B) Anemometer
• C) Hygrometer
• D) Altimeter

Correct Answer: B) Anemometer

163. Which vitamin is synthesized by intestinal bacteria?

• A) Vitamin A
• B) Vitamin K
• C) Vitamin D
• D) Vitamin C

Correct Answer: B) Vitamin K

164. The chemical name for laughing gas is:

• A) Carbon monoxide
• B) Nitrous oxide
• C) Sulfur dioxide
• D) Methane

Correct Answer: B) Nitrous oxide

165. Which is the study of insects?

• A) Ornithology
• B) Entomology
• C) Herpetology
• D) Ichthyology

Correct Answer: B) Entomology

166. The main source of geothermal energy is:

• A) Sun
• B) Earth's internal heat
• C) Wind
• D) Ocean tides

Correct Answer: B) Earth's internal heat

167. Which blood cells help in clotting?

• A) RBCs
• B) WBCs
• C) Platelets
• D) Plasma

Correct Answer: C) Platelets

168. The unit of radioactivity is:

• A) Curie
• B) Becquerel
• C) Gray
• D) Sievert

Correct Answer: B) Becquerel

169. Which planet has the shortest day?

• A) Jupiter
• B) Saturn
• C) Earth
• D) Mercury

Correct Answer: A) Jupiter

170. The chemical formula for washing soda is:

• A) NaHCO₃
• B) Na₂CO₃
• C) CaCO₃
• D) NaCl

Correct Answer: B) Na₂CO₃

171. Which organ in the human body produces insulin?

• A) Liver
• B) Pancreas
• C) Kidney
• D) Thyroid

Correct Answer: B) Pancreas

172. The phenomenon of mirage is due to:

• A) Reflection
• B) Refraction
• C) Total internal reflection
• D) Dispersion

Correct Answer: C) Total internal reflection

173. Which is the only mammal capable of true flight?

• A) Flying squirrel
• B) Bat
• C) Pterodactyl (extinct)
• D) Colugo

Correct Answer: B) Bat

174. The pH of pure water at room temperature is:

• A) 0
• B) 7
• C) 14
• D) 5

Correct Answer: B) 7

175. Which gas is used in refrigeration as a coolant?

• A) Ammonia
• B) Freon (CFCs)
• C) Carbon dioxide
• D) Oxygen

Correct Answer: B) Freon (CFCs)

176. The study of earthquakes and seismic waves is called:

• A) Volcanology
• B) Seismology
• C) Tectonics
• D) Meteorology

Correct Answer: B) Seismology

177. Which vitamin is essential for collagen synthesis?

• A) Vitamin A
• B) Vitamin C
• C) Vitamin E
• D) Vitamin B12

Correct Answer: B) Vitamin C

178. The speed of sound is highest in:

• A) Air
• B) Water
• C) Steel
• D) Vacuum

Correct Answer: C) Steel

179. Which is the universal blood donor group?

• A) AB+
• B) O-
• C) A+
• D) B-

Correct Answer: B) O-

180. The process of plants losing water through leaves is:

• A) Photosynthesis
• B) Transpiration
• C) Respiration
• D) Guttation

Correct Answer: B) Transpiration

181. Which metal is extracted from bauxite ore?

• A) Iron
• B) Aluminum
• C) Copper
• D) Zinc

Correct Answer: B) Aluminum

182. The human body's normal temperature in Fahrenheit is:

• A) 98.6°F
• B) 96.8°F
• C) 100.4°F
• D) 99.0°F

Correct Answer: A) 98.6°F

183. Which gas is released during photosynthesis?

• A) Carbon dioxide
• B) Oxygen
• C) Nitrogen
• D) Hydrogen

Correct Answer: B) Oxygen

184. The study of birds is called:

• A) Ornithology
• B) Entomology
• C) Herpetology
• D) Ichthyology

Correct Answer: A) Ornithology

185. Which is the strongest acid among common ones?

• A) Acetic acid
• B) Hydrochloric acid
• C) Citric acid
• D) Sulfuric acid

Correct Answer: D) Sulfuric acid

186. The Moon takes how many days to orbit Earth?

• A) 27.3 days
• B) 30 days
• C) 365 days
• D) 24 hours

Correct Answer: A) 27.3 days

187. Which deficiency causes goiter?

• A) Iron
• B) Iodine
• C) Calcium
• D) Vitamin D

Correct Answer: B) Iodine

188. The unit of electric charge is:

• A) Ampere
• B) Coulomb
• C) Volt
• D) Ohm

Correct Answer: B) Coulomb

189. Which is the largest planet in our solar system?

• A) Earth
• B) Jupiter
• C) Saturn
• D) Neptune

Correct Answer: B) Jupiter

190. The main constituent of hemoglobin is:

• A) Iron
• B) Calcium
• C) Magnesium
• D) Zinc

Correct Answer: A) Iron

191. Which law relates pressure and volume of gas at constant temperature?

• A) Boyle's Law
• B) Charles' Law
• C) Gay-Lussac's Law
• D) Avogadro's Law

Correct Answer: A) Boyle's Law

192. The human skeleton has how many bones in adulthood?

• A) 206
• B) 270
• C) 300
• D) 350

Correct Answer: A) 206

193. Which is the hardest naturally occurring substance?

• A) Gold
• B) Diamond
• C) Iron
• D) Platinum

Correct Answer: B) Diamond

194. The primary source of Earth's magnetic field is:

• A) Sun
• B) Molten iron in core
• C) Moon's gravity
• D) Solar wind

Correct Answer: B) Molten iron in core

195. Which acid is found in curd/yogurt?

• A) Citric acid
• B) Lactic acid
• C) Acetic acid
• D) Tartaric acid

Correct Answer: B) Lactic acid

196. The only bird that can fly backwards is:

• A) Eagle
• B) Hummingbird
• C) Ostrich
• D) Penguin

Correct Answer: B) Hummingbird

197. Which is the most abundant gas in Earth's atmosphere?

• A) Oxygen
• B) Nitrogen
• C) Carbon dioxide
• D) Argon

Correct Answer: B) Nitrogen

198. The chemical symbol for gold is:

• A) Au
• B) Ag
• C) Fe
• D) Cu

Correct Answer: A) Au

199. Which part of the brain controls breathing?

• A) Cerebrum
• B) Medulla oblongata
• C) Cerebellum
• D) Hypothalamus

Correct Answer: B) Medulla oblongata

200. The longest bone in the human body is the:

• A) Humerus
• B) Femur
• C) Tibia
• D) Radius

Correct Answer: B) Femur

201. Which instrument is used to measure the intensity of earthquakes?

• A) Richter scale
• B) Seismograph
• C) Barograph
• D) Anemograph

Correct Answer: B) Seismograph

202. The main source of vitamin A in diet is:

• A) Carrot and liver
• B) Orange
• C) Milk
• D) Fish oil

Correct Answer: A) Carrot and liver

203. Which gas is used for inflating life rafts?

• A) Helium
• B) Carbon dioxide
• C) Nitrogen
• D) Oxygen

Correct Answer: B) Carbon dioxide

204. The hardest allotrope of carbon is:

• A) Graphite
• B) Fullerene
• C) Diamond
• D) Graphene

Correct Answer: C) Diamond

205. Which part of the flower produces pollen?

• A) Ovary
• B) Stigma
• C) Anther
• D) Petal

Correct Answer: C) Anther

206. The unit of capacitance is:

• A) Farad
• B) Henry
• C) Tesla
• D) Weber

Correct Answer: A) Farad

207. Which disease is caused by the bite of Aedes mosquito?

• A) Malaria
• B) Dengue fever
• C) Yellow fever
• D) Chikungunya

Correct Answer: B) Dengue fever

208. The chemical name of quicklime is:

• A) Calcium oxide
• B) Calcium hydroxide
• C) Calcium carbonate
• D) Sodium oxide

Correct Answer: A) Calcium oxide

209. Which blood vessel carries oxygenated blood from lungs to heart?

• A) Pulmonary artery
• B) Pulmonary vein
• C) Aorta
• D) Vena cava

Correct Answer: B) Pulmonary vein

210. The SI unit of magnetic flux is:

• A) Tesla
• B) Weber
• C) Gauss
• D) Henry

Correct Answer: B) Weber

211. Which gas is released when metals react with dilute acids?

• A) Oxygen
• B) Hydrogen
• C) Carbon dioxide
• D) Nitrogen

Correct Answer: B) Hydrogen

212. The study of heredity is called:

• A) Genetics
• B) Cytology
• C) Embryology
• D) Histology

Correct Answer: A) Genetics

213. Which element is used in pencil lead?

• A) Lead
• B) Graphite
• C) Charcoal
• D) Carbon black

Correct Answer: B) Graphite

214. The normal gestation period in humans is approximately:

• A) 280 days
• B) 300 days
• C) 240 days
• D) 365 days

Correct Answer: A) 280 days

215. Which gas is used in electric arc welding?

• A) Argon
• B) Oxygen
• C) Acetylene
• D) Hydrogen

Correct Answer: C) Acetylene

216. The enzyme that helps in digestion of milk sugar is:

• A) Pepsin
• B) Lactase
• C) Amylase
• D) Lipase

Correct Answer: B) Lactase

217. Which is the primary source of energy in a food chain?

• A) Herbivores
• B) Sun
• C) Carnivores
• D) Decomposers

Correct Answer: B) Sun

218. The chemical used in photography (fixer) is:

• A) Sodium thiosulfate
• B) Silver bromide
• C) Potassium iodide
• D) Ammonium chloride

Correct Answer: A) Sodium thiosulfate

219. Which vitamin is important for healthy gums and teeth?

• A) Vitamin A
• B) Vitamin C
• C) Vitamin D
• D) Vitamin E

Correct Answer: B) Vitamin C

220. The boiling point of alcohol is:

• A) 78°C
• B) 100°C
• C) 0°C
• D) 212°C

Correct Answer: A) 78°C

250. Which is the main excretory organ in humans?

• A) Liver
• B) Skin
• C) Kidney
• D) Lungs

Correct Answer: C) Kidney

251. Which gas gives the characteristic smell to rotten eggs?

• A) Ammonia
• B) Hydrogen sulfide
• C) Sulfur dioxide
• D) Methane

Correct Answer: B) Hydrogen sulfide

252. The instrument used to measure the purity of milk is:

• A) Lactometer
• B) Hydrometer
• C) Barometer
• D) Sphygmomanometer

Correct Answer: A) Lactometer

253. Which vitamin is also called tocopherol?

• A) Vitamin A
• B) Vitamin E
• C) Vitamin K
• D) Vitamin B6

Correct Answer: B) Vitamin E

254. The main source of energy for Earth’s water cycle is:

• A) Geothermal heat
• B) Solar radiation
• C) Tidal forces
• D) Nuclear fusion in core

Correct Answer: B) Solar radiation

255. Which metal is used as a filament in incandescent bulbs?

• A) Copper
• B) Tungsten
• C) Nichrome
• D) Aluminum

Correct Answer: B) Tungsten

256. The hormone responsible for milk production in mammals is:

• A) Prolactin
• B) Oxytocin
• C) Estrogen
• D) Progesterone

Correct Answer: A) Prolactin

257. Which layer of the Sun is visible to us?

• A) Core
• B) Photosphere
• C) Chromosphere
• D) Corona

Correct Answer: B) Photosphere

258. The chemical compound responsible for the green color of leaves is:

• A) Anthocyanin
• B) Chlorophyll
• C) Xanthophyll
• D) Carotene

Correct Answer: B) Chlorophyll

259. Which gas is used in cryosurgery to freeze tissues?

• A) Nitrogen
• B) Oxygen
• C) Carbon dioxide
• D) Argon

Correct Answer: A) Nitrogen

260. The SI unit of illuminance is:

• A) Lux
• B) Lumen
• C) Candela
• D) Nit

Correct Answer: A) Lux

300. Which organ in fish helps in maintaining buoyancy?

• A) Gills
• B) Swim bladder
• C) Fins
• D) Scales

Correct Answer: B) Swim bladder

301. Which simple machine is used in a wheelbarrow to reduce effort?

• A) Pulley
• B) Lever
• C) Inclined plane
• D) Screw

Correct Answer: B) Lever

302. The substance added to soap to make it float is:

• A) Talc
• B) Air bubbles
• C) Glycerin
• D) Sodium chloride

Correct Answer: B) Air bubbles

303. Which natural phenomenon causes the twinkling of stars?

• A) Reflection
• B) Atmospheric refraction
• C) Diffraction
• D) Dispersion

Correct Answer: B) Atmospheric refraction

304. The material used in safety matches to produce flame is:

• A) Potassium chlorate
• B) Red phosphorus
• C) Sulfur
• D) Antimony trisulfide

Correct Answer: A) Potassium chlorate

305. Which part of the human ear helps in maintaining body balance?

• A) Cochlea
• B) Semicircular canals
• C) Ear drum
• D) Auditory nerve

Correct Answer: B) Semicircular canals

306. The device that converts mechanical energy into electrical energy is:

• A) Dynamo
• B) Transformer
• C) Inverter
• D) Rectifier

Correct Answer: A) Dynamo

307. Which gas is filled in electric discharge lamps to produce different colors?

• A) Neon
• B) Argon
• C) Krypton
• D) Xenon

Correct Answer: A) Neon

308. The process by which salt is removed from seawater is called:

• A) Distillation
• B) Desalination
• C) Filtration
• D) Evaporation

Correct Answer: B) Desalination

309. Which animal has the longest lifespan among common pets?

• A) Dog
• B) Cat
• C) Tortoise
• D) Parrot

Correct Answer: C) Tortoise

310. The SI unit of sound intensity level is:

• A) Decibel
• B) Hertz
• C) Phon
• D) Watt per square meter

Correct Answer: A) Decibel

311. Which substance is used as a moderator in nuclear reactors?

• A) Graphite
• B) Heavy water
• C) Boron
• D) Cadmium

Correct Answer: A) Graphite

312. The main cause of soil erosion in hilly areas is:

• A) Deforestation
• B) Overgrazing
• C) Heavy rainfall
• D) Wind

Correct Answer: A) Deforestation

313. Which metal is liquid at room temperature besides mercury?

• A) Gallium
• B) Cesium
• C) Francium
• D) Bromine (non-metal)

Correct Answer: A) Gallium

314. The pigment that gives red color to human blood is:

• A) Hemoglobin
• B) Myoglobin
• C) Chlorophyll
• D) Bilirubin

Correct Answer: A) Hemoglobin

315. Which device is used to produce artificial rain?

• A) Cloud seeding
• B) Hygrometer
• C) Rain gauge
• D) Anemometer

Correct Answer: A) Cloud seeding

316. The hardest substance in the human body is:

• A) Bone
• B) Enamel of teeth
• C) Nail
• D) Hair

Correct Answer: B) Enamel of teeth

317. Which gas is used in balloons for lifting but is not safe for deep-sea diving?

• A) Helium
• B) Hydrogen
• C) Nitrogen
• D) Oxygen

Correct Answer: B) Hydrogen

318. The process of converting vegetable oils into solid fats is called:

• A) Hydrogenation
• B) Saponification
• C) Esterification
• D) Polymerization

Correct Answer: A) Hydrogenation

319. Which bird has the largest wingspan?

• A) Eagle
• B) Albatross
• C) Ostrich
• D) Condor

Correct Answer: B) Albatross

320. The unit of electric power is:

• A) Joule
• B) Watt
• C) Ampere
• D) Volt

Correct Answer: B) Watt

321. Which acid is used in car batteries?

• A) Sulfuric acid
• B) Hydrochloric acid
• C) Nitric acid
• D) Acetic acid

Correct Answer: A) Sulfuric acid

322. The main function of red blood cells is to transport:

• A) Oxygen
• B) Carbon dioxide only
• C) Nutrients
• D) Hormones

Correct Answer: A) Oxygen

323. Which planet has rings that are the most visible from Earth?

• A) Jupiter
• B) Saturn
• C) Uranus
• D) Neptune

Correct Answer: B) Saturn

324. The chemical used to preserve food by preventing bacterial growth is:

• A) Sodium benzoate
• B) Citric acid
• C) Vinegar
• D) Salt

Correct Answer: A) Sodium benzoate

325. Which sense organ is most sensitive to touch?

• A) Lips
• B) Fingertips
• C) Tongue
• D) Ears

Correct Answer: B) Fingertips

326. The main ingredient in glass making is:

• A) Silica (sand)
• B) Lime
• C) Soda ash
• D) Potash

Correct Answer: A) Silica (sand)

327. Which animal can change color to match its surroundings?

• A) Chameleon
• B) Frog
• C) Snake
• D) Lizard

Correct Answer: A) Chameleon

328. The SI unit of frequency is:

• A) Hertz
• B) Newton
• C) Pascal
• D) Tesla

Correct Answer: A) Hertz

329. Which vitamin deficiency causes pellagra?

• A) Vitamin B3 (Niacin)
• B) Vitamin B1
• C) Vitamin C
• D) Vitamin D

Correct Answer: A) Vitamin B3 (Niacin)

330. The main source of renewable energy from water is:

• A) Tidal energy
• B) Hydroelectric power
• C) Wave energy
• D) Ocean thermal energy

Correct Answer: B) Hydroelectric power

331. Which gas is responsible for the smell of rain?

• A) Ozone
• B) Petrichor (geosmin from soil bacteria)
• C) Nitrogen
• D) Carbon monoxide

Correct Answer: B) Petrichor (geosmin from soil bacteria)

332. The device used to measure blood pressure is:

• A) Sphygmomanometer
• B) Stethoscope
• C) Thermometer
• D) Otoscope

Correct Answer: A) Sphygmomanometer

333. Which element is added to toothpaste to prevent tooth decay?

• A) Fluoride
• B) Calcium
• C) Sodium
• D) Potassium

Correct Answer: A) Fluoride

334. The main cause of rusting in iron is:

• A) Exposure to air and moisture
• B) High temperature
• C) Salt only
• D) Acid only

Correct Answer: A) Exposure to air and moisture

335. Which planet is known as the "Blue Planet"?

• A) Earth
• B) Neptune
• C) Uranus
• D) Venus

Correct Answer: A) Earth

336. The enzyme present in saliva that helps digest starch is:

• A) Amylase
• B) Pepsin
• C) Lipase
• D) Trypsin

Correct Answer: A) Amylase

337. Which gas is used in fire-fighting foam?

• A) Carbon dioxide
• B) Nitrogen
• C) Halon
• D) Argon

Correct Answer: A) Carbon dioxide

338. The smallest bone in the human body is located in the:

• A) Ear
• B) Nose
• C) Finger
• D) Toe

Correct Answer: A) Ear

339. Which process turns milk into yogurt?

• A) Fermentation
• B) Pasteurization
• C) Homogenization
• D) Coagulation

Correct Answer: A) Fermentation

340. The main gas in exhaled air is:

• A) Oxygen
• B) Nitrogen
• C) Carbon dioxide
• D) Argon

Correct Answer: B) Nitrogen

341. Which animal has three hearts?

• A) Octopus
• B) Earthworm
• C) Frog
• D) Snake

Correct Answer: A) Octopus

342. The unit of work or energy in SI system is:

• A) Joule
• B) Newton
• C) Watt
• D) Pascal

Correct Answer: A) Joule

343. Which vitamin is produced in the skin on exposure to sunlight?

• A) Vitamin A
• B) Vitamin D
• C) Vitamin E
• D) Vitamin K

Correct Answer: B) Vitamin D

344. The main component of LPG (liquefied petroleum gas) is:

• A) Methane
• B) Propane and butane
• C) Ethane
• D) Pentane

Correct Answer: B) Propane and butane

345. Which is the only metal that is liquid at room temperature?

• A) Mercury
• B) Gallium
• C) Cesium
• D) Bromine

Correct Answer: A) Mercury

346. The study of weather patterns over long periods is called:

• A) Meteorology
• B) Climatology
• C) Seismology
• D) Oceanography

Correct Answer: B) Climatology

347. Which acid is present in vinegar?

• A) Acetic acid
• B) Citric acid
• C) Lactic acid
• D) Tartaric acid

Correct Answer: A) Acetic acid

348. The device used to measure humidity in air is:

• A) Hygrometer
• B) Barometer
• C) Thermometer
• D) Anemometer

Correct Answer: A) Hygrometer

349. Which is the fastest flying bird?

• A) Peregrine falcon
• B) Swift
• C) Eagle
• D) Hummingbird

Correct Answer: A) Peregrine falcon

350. The chemical formula for table sugar is:

• A) C6H12O6
• B) C12H22O11
• C) C6H6
• D) NaCl

Correct Answer: B) C12H22O11

351. Which everyday item was originally invented to hold ice cream cones steady?

• A) Spoon
• B) Paper cup
• C) Napkin holder
• D) Straw

Correct Answer: B) Paper cup

352. The white part of an egg is mainly made of:

• A) Protein (albumin)
• B) Fat
• C) Carbohydrate
• D) Minerals

Correct Answer: A) Protein (albumin)

353. Which common household substance can be used to neutralize an acid spill?

• A) Baking soda
• B) Vinegar
• C) Lemon juice
• D) Salt

Correct Answer: A) Baking soda

354. The reason ice floats on water is because:

• A) Ice is less dense than liquid water
• B) Ice is colder
• C) Water expands when heated
• D) Ice has more molecules

Correct Answer: A) Ice is less dense than liquid water

355. Which part of a plant absorbs water and minerals from the soil?

• A) Stem
• B) Leaves
• C) Root hairs
• D) Flowers

Correct Answer: C) Root hairs

356. The device used in homes to detect smoke and fire is called a:

• A) Thermostat
• B) Smoke detector
• C) Carbon monoxide alarm
• D) Gas leak sensor

Correct Answer: B) Smoke detector

357. Which everyday material is made by mixing cement, sand, gravel, and water?

• A) Brick
• B) Concrete
• C) Plaster
• D) Mortar

Correct Answer: B) Concrete

358. The main reason we feel cooler after sweating is due to:

• A) Evaporation
• B) Conduction
• C) Radiation
• D) Convection

Correct Answer: A) Evaporation

359. Which common fruit contains an enzyme that tenderizes meat?

• A) Pineapple (bromelain)
• B) Apple
• C) Banana
• D) Orange

Correct Answer: A) Pineapple (bromelain)

360. The reason a compass needle points north is due to Earth's:

• A) Magnetic field
• B) Gravity
• C) Rotation
• D) Atmosphere

Correct Answer: A) Magnetic field

400. Which everyday object uses the principle of Bernoulli to create lift?

• A) Airplane wing
• B) Ceiling fan
• C) Vacuum cleaner
• D) Hair dryer

Correct Answer: A) Airplane wing

401. Which household item was originally created to remove pencil marks?

• A) Rubber eraser
• B) Sandpaper
• C) White-out
• D) Blade

Correct Answer: A) Rubber eraser

402. The main reason balloons rise when filled with helium is:

• A) Helium is lighter than air
• B) Helium is hot
• C) Helium produces lift force
• D) Helium reacts with rubber

Correct Answer: A) Helium is lighter than air

403. Which common kitchen ingredient can be used as a natural antacid?

• A) Baking soda
• B) Lemon juice
• C) Vinegar
• D) Salt

Correct Answer: A) Baking soda

404. The curved shape of a spoon can act as a:

• A) Convex mirror
• B) Concave mirror
• C) Plane mirror
• D) Lens

Correct Answer: B) Concave mirror

405. Which part of the human body continues to grow even after death for a short time?

• A) Hair and nails (appear to due to skin shrinkage)
• B) Bones
• C) Teeth
• D) Eyes

Correct Answer: A) Hair and nails (appear to due to skin shrinkage)

406. The popping sound when you open a soda bottle is caused by:

• A) Release of dissolved carbon dioxide
• B) Oxygen escaping
• C) Nitrogen bubbles
• D) Temperature change

Correct Answer: A) Release of dissolved carbon dioxide

407. Which everyday fabric is made from the cocoon of a silkworm?

• A) Silk
• B) Cotton
• C) Wool
• D) Nylon

Correct Answer: A) Silk

408. The blue color of the ocean is mainly due to:

• A) Scattering of blue light by water molecules
• B) Reflection of sky
• C) Algae
• D) Minerals in water

Correct Answer: A) Scattering of blue light by water molecules

409. Which common gas is used in potato chip packets to keep them fresh and crispy?

• A) Nitrogen
• B) Oxygen
• C) Carbon dioxide
• D) Helium

Correct Answer: A) Nitrogen

410. The cracking sound when you crack your knuckles is caused by:

• A) Collapse of gas bubbles in synovial fluid
• B) Bone rubbing
• C) Ligament snap
• D) Muscle contraction

Correct Answer: A) Collapse of gas bubbles in synovial fluid

411. Which everyday material is biodegradable and made from plant starch?

• A) PLA plastic
• B) Polyethylene
• C) PVC
• D) Polystyrene

Correct Answer: A) PLA plastic

412. The faint glow seen in some deep-sea creatures is called:

• A) Bioluminescence
• B) Fluorescence
• C) Phosphorescence
• D) Chemiluminescence

Correct Answer: A) Bioluminescence

413. Which common spice contains the compound capsaicin that causes a burning sensation?

• A) Chili pepper
• B) Black pepper
• C) Cinnamon
• D) Turmeric

Correct Answer: A) Chili pepper

414. The reason a straw appears bent in a glass of water is due to:

• A) Refraction of light
• B) Reflection
• C) Diffraction
• D) Dispersion

Correct Answer: A) Refraction of light

415. Which natural fiber is obtained from the flax plant?

• A) Linen
• B) Cotton
• C) Jute
• D) Hemp

Correct Answer: A) Linen

416. The slight purple tint in some drinking water bottles is added to:

• A) Block UV light and prevent algae growth
• B) Improve taste
• C) Increase strength
• D) Reduce weight

Correct Answer: A) Block UV light and prevent algae growth

417. Which common fruit produces ethylene gas that speeds up ripening of other fruits?

• A) Banana
• B) Apple
• C) Mango
• D) All of the above

Correct Answer: D) All of the above

418. The main reason birds have hollow bones is to:

• A) Reduce body weight for flight
• B) Increase strength
• C) Store fat
• D) Improve hearing

Correct Answer: A) Reduce body weight for flight

419. Which everyday liquid has the highest surface tension?

• A) Water
• B) Mercury
• C) Alcohol
• D) Oil

Correct Answer: B) Mercury

420. The green color on old copper objects (patina) is mainly:

• A) Copper carbonate
• B) Copper oxide
• C) Copper sulfate
• D) Copper chloride

Correct Answer: A) Copper carbonate

421. Which common kitchen tool demonstrates the principle of a first-class lever?

• A) Scissors
• B) Nutcracker
• C) Bottle opener
• D) Wheelbarrow

Correct Answer: A) Scissors

422. The slight rainbow colors seen on soap bubbles are caused by:

• A) Interference of light
• B) Reflection only
• C) Refraction only
• D) Dispersion only

Correct Answer: A) Interference of light

423. Which natural material is used to make charcoal for drawing and grilling?

• A) Burnt wood
• B) Coal
• C) Graphite
• D) Limestone

Correct Answer: A) Burnt wood

424. The reason a pressure cooker cooks food faster is mainly because:

• A) Boiling point of water increases under pressure
• B) Heat is trapped
• C) Steam condenses quickly
• D) Food absorbs more heat

Correct Answer: A) Boiling point of water increases under pressure

425. Which everyday object uses a bimetallic strip to control temperature?

• A) Electric iron thermostat
• B) Ceiling fan
• C) Refrigerator compressor
• D) Microwave magnetron

Correct Answer: A) Electric iron thermostat

426. The black coating on the inside of non-stick pans is usually:

• A) Teflon (PTFE)
• B) Ceramic
• C) Enamel
• D) Aluminum oxide

Correct Answer: A) Teflon (PTFE)

427. Which common gas is produced when yeast ferments sugar in dough?

• A) Carbon dioxide
• B) Oxygen
• C) Hydrogen
• D) Nitrogen

Correct Answer: A) Carbon dioxide

428. The reason we can see our breath on cold days is:

• A) Water vapor condensing into tiny droplets
• B) Carbon dioxide freezing
• C) Oxygen turning white
• D) Nitrogen solidifying

Correct Answer: A) Water vapor condensing into tiny droplets

429. Which common household acid is used to clean limescale from kettles?

• A) Vinegar (acetic acid)
• B) Lemon juice (citric acid)
• C) Both A and B
• D) Hydrochloric acid

Correct Answer: C) Both A and B

430. The device in a car that converts chemical energy into electrical energy is the:

• A) Battery
• B) Alternator
• C) Starter motor
• D) Spark plug

Correct Answer: A) Battery

431. Which common kitchen process causes bread to rise?

• A) Fermentation by yeast producing CO₂
• B) Baking powder reaction
• C) Maillard reaction
• D) Caramelization

Correct Answer: A) Fermentation by yeast producing CO₂