General Science Quiz: 25 Essential Questions & Answers
Test your knowledge of fundamental science concepts with this curated quiz. Each question includes a clear explanation to enhance your understanding.
1. SI Unit of Electric Current
Which of the following is the SI unit of electric current?
- (a) Volt
- (b) Ohm
- (c) Ampere
- (d) Watt
Answer: (c) Ampere
Explanation: The ampere (A) is the SI base unit for electric current. It is defined as one coulomb of electric charge passing per second.
2. Light Scattering in Colloids
The phenomenon of scattering of light by particles in a colloid, making the light beam visible, is known as:
- (a) Tyndall effect
- (b) Raman effect
- (c) Doppler effect
- (d) Photoelectric effect
Answer: (a) Tyndall effect
Explanation: The Tyndall effect describes the scattering of light by colloidal particles or fine suspensions, making the path of the beam visible.
3. Most Abundant Atmospheric Gas
Which gas is most abundant in Earth’s atmosphere?
- (a) Oxygen
- (b) Carbon dioxide
- (c) Nitrogen
- (d) Argon
Answer: (c) Nitrogen
Explanation: Nitrogen (N₂) constitutes approximately 78% of Earth’s atmosphere by volume, making it the most abundant gas.
4. pH of a Neutral Solution
The pH of a neutral solution at 25°C is:
- (a) 0
- (b) 7
- (c) 14
- (d) 1
Answer: (b) 7
Explanation: At 25°C, a neutral solution like pure water has equal concentrations of H⁺ and OH⁻ ions, resulting in a pH of 7.
5. Identifying a Vector Quantity
Which of the following is a vector quantity?
- (a) Speed
- (b) Distance
- (c) Displacement
- (d) Mass
Answer: (c) Displacement
Explanation: Displacement has both magnitude and direction, defining it as a vector. Speed, distance, and mass are scalar quantities with magnitude only.
6. Plant Water Loss Process
The process by which plants lose water vapor through small openings in their leaves is called:
- (a) Transpiration
- (b) Respiration
- (c) Photosynthesis
- (d) Guttation
Answer: (a) Transpiration
Explanation: Transpiration is the loss of water vapor from aerial parts of a plant, primarily through stomata in the leaves.
7. Primary Detoxification Organ
Which organ in the human body is primarily responsible for detoxification?
- (a) Kidney
- (b) Liver
- (c) Heart
- (d) Lungs
Answer: (b) Liver
Explanation: The liver is the main detoxification center, metabolizing and neutralizing drugs, toxins, and waste products.
8. Chemical Formula of Table Salt
The chemical formula of table salt is:
- (a) KCl
- (b) Na₂SO₄
- (c) NaCl
- (d) CaCO₃
Answer: (c) NaCl
Explanation: Common table salt is sodium chloride, with the chemical formula NaCl.
9. Hardest Natural Substance
Which of the following is the hardest naturally occurring substance?
- (a) Graphite
- (b) Quartz
- (c) Diamond
- (d) Talc
Answer: (c) Diamond
Explanation: Diamond, an allotrope of carbon, ranks as a 10 on the Mohs hardness scale, making it the hardest known natural material.
10. Eye Structure Controlling Light
In the human eye, the structure that controls the amount of light entering the eye is the:
- (a) Retina
- (b) Cornea
- (c) Iris
- (d) Lens
Answer: (c) Iris
Explanation: The iris contains muscles that adjust the size of the pupil, thereby regulating the quantity of light that enters the eye.
11. Fire Extinguisher for Electrical Fires
Which gas is commonly used in fire extinguishers for electrical fires?
- (a) Carbon dioxide
- (b) Hydrogen
- (c) Methane
- (d) Oxygen
Answer: (a) Carbon dioxide
Explanation: Carbon dioxide (CO₂) is non-conductive and displaces oxygen, making it effective and safe for suppressing electrical fires.
12. Chromosomes in Human Gametes
The number of chromosomes in a normal human gamete (sperm or egg) is:
- (a) 23
- (b) 46
- (c) 22
- (d) 24
Answer: (a) 23
Explanation: Human somatic cells are diploid (46 chromosomes). Gametes are haploid, containing half that number, or 23 chromosomes.
13. Acid Present in Vinegar
Which of the following acids is present in vinegar?
- (a) Citric acid
- (b) Acetic acid
- (c) Lactic acid
- (d) Tartaric acid
Answer: (b) Acetic acid
Explanation: Vinegar is primarily a dilute aqueous solution of acetic acid (CH₃COOH).
14. SI Unit of Work
The SI unit of work is:
- (a) Newton
- (b) Joule
- (c) Watt
- (d) Pascal
Answer: (b) Joule
Explanation: Work and energy are measured in joules (J). One joule is defined as the work done by a force of one newton over a displacement of one meter (1 J = 1 N·m).
15. Brain Region for Heartbeat & Respiration
Which part of the brain is responsible for regulating heartbeat and respiration?
- (a) Cerebrum
- (b) Cerebellum
- (c) Medulla oblongata
- (d) Thalamus
Answer: (c) Medulla oblongata
Explanation: The medulla oblongata, located in the brainstem, controls vital autonomic functions including heart rate, breathing, and blood pressure.
16. Organelle for Photosynthesis
Photosynthesis primarily occurs in which cell organelle?
- (a) Mitochondria
- (b) Chloroplast
- (c) Nucleus
- (d) Ribosome
Answer: (b) Chloroplast
Explanation: Chloroplasts are the organelles in plant cells that contain chlorophyll and are the site of photosynthesis.
17. Non-Renewable Energy Source
Which of the following is a non‑renewable source of energy?
- (a) Solar
- (b) Wind
- (c) Coal
- (d) Biomass
Answer: (c) Coal
Explanation: Coal is a fossil fuel. It is formed over geological timescales and cannot be replenished at the rate it is consumed, classifying it as non-renewable.
18. Common Refrigerant
The refrigerant commonly used in domestic refrigerators is:
- (a) Ammonia
- (b) Freon‑12 (CFC‑12)
- (c) Carbon dioxide
- (d) Sulphur dioxide
Answer: (b) Freon‑12 (CFC‑12)
Explanation: Historically, dichlorodifluoromethane (Freon-12 or CFC-12) was the standard refrigerant. Modern units often use more environmentally friendly alternatives, but it remains the classic answer.
19. Vitamin Synthesized by Sunlight
Which vitamin is synthesized by the human skin upon exposure to sunlight?
- (a) Vitamin A
- (b) Vitamin C
- (c) Vitamin D
- (d) Vitamin K
Answer: (c) Vitamin D
Explanation: Exposure to UV-B sunlight converts 7‑dehydrocholesterol in the skin into previtamin D₃, which is then processed into active vitamin D.
20. Sugar Conversion by Yeast
The process of converting sugar into alcohol and carbon dioxide by yeast is called:
- (a) Fermentation
- (b) Oxidation
- (c) Hydrolysis
- (d) Polymerization
Answer: (a) Fermentation
Explanation: Fermentation is the anaerobic metabolic process where yeast converts sugars (like glucose) into ethanol and carbon dioxide.
21. Correct Statement About Isotopes
Which of the following statements about isotopes is correct?
- (a) Isotopes have different numbers of protons.
- (b) Isotopes of an element have the same mass number.
- (c) Isotopes have the same number of protons but different numbers of neutrons.
- (d) Isotopes have different chemical properties.
Answer: (c)
Explanation: Isotopes are variants of an element that share the same atomic number (proton count) but have different numbers of neutrons, resulting in different mass numbers.
22. Bending of Light Between Media
The phenomenon where a beam of light changes direction when passing from one medium to another with different optical density is called:
- (a) Reflection
- (b) Refraction
- (c) Diffraction
- (d) Scattering
Answer: (b) Refraction
Explanation: Refraction is the bending of a light wave as it passes from one medium to another with a different refractive index, caused by a change in its speed.
23. Primary Pollutant for Acid Rain
Which of the following is a primary pollutant responsible for acid rain?
- (a) Carbon monoxide
- (b) Sulfur dioxide
- (c) Methane
- (d) Ozone
Answer: (b) Sulfur dioxide
Explanation: Sulfur dioxide (SO₂) from burning fossil fuels reacts with atmospheric water and oxygen to form sulfuric acid, a major contributor to acid rain.
24. Universal Blood Donor
The human blood group that is considered the universal donor
