These 60 MCQ questions cover the most frequently tested General Science topics in UPSC, SSC CGL, Railways Group D, NTPC and other competitive examinations 2026. Questions are divided into Physics, Chemistry and Biology. Click Show Answer to see detailed explanations. For unlimited daily science MCQ practice, visit Vooo AI Education.

⚡ Physics (Q1–Q20)
1The SI unit of force is:
A. Joule
B. Newton
C. Watt
D. Pascal
Answer: B — Newton
The SI unit of force is Newton (N), named after Sir Isaac Newton. 1 Newton = 1 kg·m/s². Joule is energy, Watt is power, Pascal is pressure.
2Which mirror is used in car headlights?
A. Convex mirror
B. Concave mirror
C. Plane mirror
D. Parabolic mirror
Answer: B — Concave mirror
Concave mirrors are used in car headlights to produce a parallel beam of light. The bulb is placed at the focus of the concave mirror.
3The unit of electrical resistance is:
A. Ampere
B. Volt
C. Ohm
D. Watt
Answer: C — Ohm
The SI unit of electrical resistance is Ohm (Ω), named after Georg Simon Ohm. V=IR (Ohm's Law) where R is resistance in Ohms.
4Which instrument measures atmospheric pressure?
A. Barometer
B. Thermometer
C. Hygrometer
D. Anemometer
Answer: A — Barometer
A Barometer measures atmospheric pressure. Thermometer measures temperature, Hygrometer measures humidity, Anemometer measures wind speed.
5Newton's first law of motion is also called:
A. Law of Inertia
B. Law of Acceleration
C. Law of Action-Reaction
D. Law of Gravitation
Answer: A — Law of Inertia
Newton's First Law states that a body at rest stays at rest and a body in motion stays in motion unless acted upon by an external force. This is called the Law of Inertia.
6The phenomenon of light bending when it passes from one medium to another is called:
A. Reflection
B. Refraction
C. Diffraction
D. Dispersion
Answer: B — Refraction
Refraction is the bending of light as it passes from one medium to another (e.g., air to water). It is responsible for the apparent bending of a stick in water.
7The SI unit of energy is:
A. Joule
B. Newton
C. Watt
D. Pascal
Answer: A — Joule
The SI unit of energy and work is Joule (J). 1 Joule = 1 Newton × 1 metre. Named after physicist James Prescott Joule.
8Which type of lens is used to correct myopia (short-sightedness)?
A. Convex lens
B. Concave lens
C. Bifocal lens
D. Cylindrical lens
Answer: B — Concave lens
Myopia (short-sightedness) is corrected using a concave (diverging) lens. Hypermetropia (long-sightedness) is corrected using a convex lens.

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🧪 Chemistry (Q9–Q20)
9The atomic number of Carbon is:
A. 4
B. 5
C. 6
D. 8
Answer: C — 6
Carbon has atomic number 6, meaning it has 6 protons in its nucleus. Carbon is the basis of all organic chemistry and life on Earth.
10Baking soda is chemically known as:
A. Sodium Chloride
B. Sodium Bicarbonate
C. Sodium Carbonate
D. Sodium Hydroxide
Answer: B — Sodium Bicarbonate
Baking soda is NaHCO₃ (Sodium Bicarbonate). It releases CO₂ when heated or mixed with acid, causing baked goods to rise.
11Which gas is produced when zinc reacts with dilute sulphuric acid?
A. Hydrogen
B. Oxygen
C. Carbon dioxide
D. Sulphur dioxide
Answer: A — Hydrogen
Zn + H₂SO₄ → ZnSO₄ + H₂↑. When zinc reacts with dilute sulphuric acid, zinc sulphate and hydrogen gas are produced.
12pH of pure water is:
A. 0
B. 5
C. 7
D. 14
Answer: C — 7
Pure water has a pH of 7, which is neutral. pH below 7 is acidic, above 7 is basic/alkaline.
13The most abundant gas in Earth's atmosphere is:
A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Argon
Answer: B — Nitrogen
Nitrogen makes up about 78% of Earth's atmosphere. Oxygen is about 21%, Argon about 0.9%, and CO₂ about 0.04%.
14Rust is chemically:
A. Iron Sulphide
B. Hydrated Iron Oxide
C. Iron Carbonate
D. Iron Chloride
Answer: B — Hydrated Iron Oxide
Rust is Fe₂O₃·xH₂O (Hydrated Iron(III) Oxide). It forms when iron is exposed to oxygen and moisture through the process of oxidation.
🌱 Biology (Q15–Q25)
15The powerhouse of the cell is:
A. Nucleus
B. Mitochondria
C. Ribosome
D. Golgi body
Answer: B — Mitochondria
Mitochondria are called the powerhouse of the cell because they produce ATP (adenosine triphosphate), the primary energy currency of the cell through cellular respiration.
16Which organ produces insulin in the human body?
A. Liver
B. Kidney
C. Pancreas
D. Stomach
Answer: C — Pancreas
Insulin is produced by beta cells of the islets of Langerhans in the pancreas. Insulin regulates blood glucose levels. Deficiency causes diabetes mellitus.
17The process by which plants make food is called:
A. Respiration
B. Photosynthesis
C. Transpiration
D. Germination
Answer: B — Photosynthesis
Photosynthesis: 6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂. Plants convert carbon dioxide and water into glucose using sunlight and chlorophyll.
18The largest organ in the human body is:
A. Skin
B. Liver
C. Brain
D. Lungs
Answer: A — Skin
The skin is the largest organ of the human body, covering about 1.5-2 square metres. The liver is the largest internal organ.
19Which vitamin is essential for blood clotting?
A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin K
Answer: D — Vitamin K
Vitamin K is essential for blood clotting. It helps produce prothrombin and other clotting factors. Deficiency causes excessive bleeding.
20The scientific name of humans is:
A. Homo erectus
B. Homo sapiens
C. Homo habilis
D. Pan troglodytes
Answer: B — Homo sapiens
The scientific name of modern humans is Homo sapiens, meaning "wise man" in Latin. Pan troglodytes is the chimpanzee.

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