The Ever-Evolving World of Science Part 4: MCQs (Q76–Q100)
📘 Chapter 1 – The Ever-Evolving World of Science
Part 4: MCQs (Q76–Q100)
Sub-Topics: Introduction to Science, Science in Everyday Life
Q76. Which of these is NOT an example of force in daily life?
A) Kicking a football
B) Pulling a door
C) Pushing a trolley
D) Reading a book
✅ Correct Answer: D) Reading a book
Explanation:
- A) Kicking – Force applied.
- B) Pulling – Force applied.
- C) Pushing – Force applied.
- D) Reading a book – Correct, no physical force involved.
Q77. Which scientist discovered the law of planetary motion?
A) Newton
B) Kepler
C) Galileo
D) Einstein
✅ Correct Answer: B) Kepler
Explanation:
- A) Newton – Law of gravitation.
- B) Kepler – Correct, laws of planetary motion.
- C) Galileo – Supported heliocentrism.
- D) Einstein – Theory of relativity.
Q78. Which of these appliances works on the principle of convection of heat?
A) Electric iron
B) Geyser
C) Refrigerator
D) Room heater
✅ Correct Answer: D) Room heater
Explanation:
- A) Iron – Conduction of heat.
- B) Geyser – Mainly conduction + heating coil.
- C) Refrigerator – Cooling mechanism, not convection.
- D) Room heater – Correct, warm air rises and circulates.
Q79. Which of these is NOT a use of science in medicine?
A) X-rays
B) MRI scan
C) Vaccination
D) Astrology
✅ Correct Answer: D) Astrology
Explanation:
- A) X-rays – Diagnostic tool.
- B) MRI – Medical imaging.
- C) Vaccination – Prevents diseases.
- D) Astrology – Correct, not scientific medicine.
Q80. Which of the following devices is used to measure speed of wind?
A) Barometer
B) Hygrometer
C) Anemometer
D) Speedometer
✅ Correct Answer: C) Anemometer
Explanation:
- A) Barometer – Pressure.
- B) Hygrometer – Humidity.
- C) Anemometer – Correct, wind speed.
- D) Speedometer – Speed of vehicles.
Q81. Which of these shows the transformation of chemical energy into electrical energy?
A) Battery
B) Fan
C) Bulb
D) Speaker
✅ Correct Answer: A) Battery
Explanation:
- A) Battery – Correct, stores chemical energy, gives electrical.
- B) Fan – Electrical → Mechanical.
- C) Bulb – Electrical → Light.
- D) Speaker – Electrical → Sound.
Q82. Which of these shows an irreversible change?
A) Melting wax
B) Freezing water
C) Burning paper
D) Boiling water
✅ Correct Answer: C) Burning paper
Explanation:
- A) Melting – Reversible.
- B) Freezing – Reversible.
- C) Burning paper – Correct, irreversible, new substances formed.
- D) Boiling – Reversible.
Q83. Which gas is necessary for photosynthesis?
A) Oxygen
B) Carbon dioxide
C) Nitrogen
D) Helium
✅ Correct Answer: B) Carbon dioxide
Explanation:
- A) Oxygen – Released during photosynthesis.
- B) Carbon dioxide – Correct, taken in by plants.
- C) Nitrogen – Needed for proteins but not directly absorbed.
- D) Helium – Not involved.
Q84. Which scientist is credited with discovering the cell?
A) Robert Hooke
B) Leeuwenhoek
C) Mendel
D) Darwin
✅ Correct Answer: A) Robert Hooke
Explanation:
- A) Hooke – Correct, observed cells in cork (1665).
- B) Leeuwenhoek – First saw living cells/microbes.
- C) Mendel – Genetics.
- D) Darwin – Evolution.
Q85. Which of these is an example of biotechnology in agriculture?
A) Using tractors
B) Hybrid seeds
C) Solar pumps
D) Plastic pipes
✅ Correct Answer: B) Hybrid seeds
Explanation:
- A) Tractors – Mechanical technology.
- B) Hybrid seeds – Correct, scientific breeding method.
- C) Pumps – Mechanical aid.
- D) Pipes – Tools, not biotech.
Q86. Which of these is a use of reflection of light?
A) Periscope
B) Microscope
C) Telescope
D) Lens in spectacles
✅ Correct Answer: A) Periscope
Explanation:
- A) Periscope – Correct, uses mirrors for reflection.
- B) Microscope – Refraction, magnification.
- C) Telescope – Refraction/reflection, but more complex.
- D) Spectacles – Refraction.
Q87. Which energy source is obtained from inside the Earth?
A) Solar
B) Geothermal
C) Hydropower
D) Nuclear
✅ Correct Answer: B) Geothermal
Explanation:
- A) Solar – Sunlight.
- B) Geothermal – Correct, heat from Earth’s interior.
- C) Hydropower – Water.
- D) Nuclear – Atomic reactions.
Q88. Which of these shows Newton’s first law of motion (inertia)?
A) Ball continues rolling until stopped
B) Rocket launch
C) Swinging pendulum
D) Pressure cooker whistle
✅ Correct Answer: A) Ball continues rolling until stopped
Explanation:
- A) Rolling ball – Correct, inertia keeps it moving.
- B) Rocket – Third law.
- C) Pendulum – Periodic motion, not inertia alone.
- D) Whistle – Pressure, not inertia.
Q89. Which scientist discovered the circulation of blood?
A) William Harvey
B) Louis Pasteur
C) Gregor Mendel
D) Robert Koch
✅ Correct Answer: A) William Harvey
Explanation:
- A) Harvey – Correct, discovered blood circulation.
- B) Pasteur – Germ theory.
- C) Mendel – Genetics.
- D) Koch – Disease-causing microbes.
Q90. Which of these is NOT a source of light?
A) Candle
B) Sun
C) Mirror
D) Torch
✅ Correct Answer: C) Mirror
Explanation:
- A) Candle – Produces light.
- B) Sun – Natural light source.
- C) Mirror – Correct, reflects light, doesn’t produce.
- D) Torch – Produces light with battery.
Q91. Which branch of science studies fossils and ancient life forms?
A) Botany
B) Zoology
C) Paleontology
D) Astronomy
✅ Correct Answer: C) Paleontology
Explanation:
- A) Botany – Plants.
- B) Zoology – Animals.
- C) Paleontology – Correct, fossils and ancient organisms.
- D) Astronomy – Space.
Q92. Which of these is an application of magnets in daily life?
A) Refrigerator doors
B) Credit card strips
C) Electric motors
D) All of the above
✅ Correct Answer: D) All of the above
Explanation:
- A) Fridge doors – Use magnetic strips.
- B) Credit cards – Magnetic stripe technology.
- C) Motors – Use electromagnets.
- D) All – Correct, all are applications.
Q93. Which of these scientists discovered the electron?
A) J.J. Thomson
B) Rutherford
C) Bohr
D) Dalton
✅ Correct Answer: A) J.J. Thomson
Explanation:
- A) Thomson – Correct, discovered electron.
- B) Rutherford – Nucleus discovery.
- C) Bohr – Planetary model of atom.
- D) Dalton – Atomic theory.
Q94. Which of these is an example of refraction in daily life?
A) Coin appearing raised in water
B) Image in mirror
C) Shadow formation
D) Echo
✅ Correct Answer: A) Coin appearing raised in water
Explanation:
- A) Raised coin – Correct, bending of light (refraction).
- B) Mirror – Reflection.
- C) Shadow – Light obstruction.
- D) Echo – Sound reflection.
Q95. Which instrument is used to measure electric current?
A) Voltmeter
B) Ammeter
C) Barometer
D) Hygrometer
✅ Correct Answer: B) Ammeter
Explanation:
- A) Voltmeter – Voltage.
- B) Ammeter – Correct, measures current.
- C) Barometer – Pressure.
- D) Hygrometer – Humidity.
Q96. Which gas is commonly used in balloons because it is lighter than air?
A) Oxygen
B) Nitrogen
C) Helium
D) Carbon dioxide
✅ Correct Answer: C) Helium
Explanation:
- A) Oxygen – Supports burning, not used.
- B) Nitrogen – Heavier than helium.
- C) Helium – Correct, safe, lighter than air.
- D) CO₂ – Heavier than air.
Q97. Which of these inventions uses electromagnetic waves?
A) Radio
B) X-ray machine
C) Microwave oven
D) All of the above
✅ Correct Answer: D) All of the above
Explanation:
- A) Radio – Uses radio waves.
- B) X-ray machine – Uses X-rays.
- C) Microwave – Uses microwaves.
- D) All – Correct, all involve electromagnetic waves.
Q98. Which of these is a natural satellite?
A) Mars
B) Moon
C) Venus
D) Jupiter
✅ Correct Answer: B) Moon
Explanation:
- A) Mars – Planet.
- B) Moon – Correct, Earth’s natural satellite.
- C) Venus – Planet.
- D) Jupiter – Planet with many moons.
Q99. Which scientist gave the three laws of motion?
A) Newton
B) Galileo
C) Einstein
D) Copernicus
✅ Correct Answer: A) Newton
Explanation:
- A) Newton – Correct, laws of motion.
- B) Galileo – Early motion studies.
- C) Einstein – Relativity.
- D) Copernicus – Heliocentric theory.
Q100. Which of these is the best example of science improving human life?
A) Superstitions
B) Vaccines
C) Blind beliefs
D) Magic tricks
✅ Correct Answer: B) Vaccines
Explanation:
- A) Superstitions – Opposite of science.
- B) Vaccines – Correct, protect from deadly diseases.
- C) Blind beliefs – Unscientific.
- D) Magic tricks – Entertainment, not science.
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