Question 1

Which color absorbs the most heat?

Accepted Answer

Correct Answer: Black

Explanation: Black color absorbs the most heat because it absorbs all wavelengths of light and reflects none. The absorbed light energy is converted into heat energy. This is why wearing black clothes in summer feels hotter than wearing white, which reflects most light and stays cooler.

Question 2

What is the chemical formula of Salt?

Accepted Answer

Correct Answer: NaCl

Explanation: Common Salt (Table Salt) is Sodium Chloride (NaCl). It forms a crystal lattice structure. It is crucial for human health, helping to transmit nerve impulses and maintain fluid balance. Historically, it was so valuable for food preservation that it was used as currency (origin of the word 'salary').

Question 3

Which part of the brain controls memory?

Accepted Answer

Correct Answer: Hippocampus / Cerebrum

Explanation: The Hippocampus (part of the Cerebrum) plays a critical role in the formation of new memories and connecting emotions to those memories. Damage to this area can lead to the inability to form new long-term memories (amnesia). The Cerebrum as a whole is responsible for higher functions like thinking and memory.

Question 4

The nearest star to Earth (after Sun) is:

Accepted Answer

Correct Answer: Proxima Centauri

Explanation: Proxima Centauri is the closest star to our Solar System, located about 4.24 light-years away. It is a red dwarf star in the constellation Centaurus. It is part of the Alpha Centauri star system. Despite being the closest, it is too faint to be seen with the naked eye.

Question 5

Which gas is used in fire extinguishers?

Accepted Answer

Correct Answer: Carbon Dioxide

Explanation: Carbon Dioxide (CO2) is used in fire extinguishers. It is heavier than air and non-flammable. When released, it blankets the fire, cutting off the supply of oxygen that the fire needs to burn. It also cools the fuel. It is effective on electrical fires and liquid fires.

Question 6

What is the SI unit of Force?

Accepted Answer

Correct Answer: Newton

Explanation: The SI unit of force is the Newton (N). One Newton is the force required to accelerate a mass of one kilogram by one meter per second squared (F=ma). It is named after Sir Isaac Newton for his work on the laws of motion and gravity.

Question 7

Which planet has the most moons?

Accepted Answer

Correct Answer: Saturn

Explanation: Saturn currently holds the record for the most moons in the solar system, with over 140 confirmed moons (including Titan). This number surpassed Jupiter after the discovery of several small moons in recent years. These moons range from tiny rocks to massive worlds with their own atmospheres.

Question 8

The purity of Milk is measured by:

Accepted Answer

Correct Answer: Lactometer

Explanation: A Lactometer is used to test the purity of milk. It measures the specific gravity (density) of the milk. Since milk is denser than water, adding water lowers its density. The lactometer floats at different levels depending on the density, allowing detection of adulteration with water.

Question 9

Which acid is present in Ant Stings?

Accepted Answer

Correct Answer: Formic Acid

Explanation: Ant stings (and bee stings) contain Formic Acid (Methanoic Acid). When an ant bites, it injects this acid into the skin, causing a stinging sensation, pain, and redness. It is a defense mechanism. Applying a mild base like baking soda can neutralize the acid and provide relief.

Question 10

Who invented the Steam Engine?

Accepted Answer

Correct Answer: James Watt

Explanation: James Watt, a Scottish inventor, significantly improved the steam engine in 1776 (originally developed by Newcomen). His design was much more efficient and practical, making it the driving force behind the Industrial Revolution. The unit of power, the Watt, is named in his honor.

Question 11

Which element is found in Hemoglobin?

Accepted Answer

Correct Answer: Iron

Explanation: Iron (Fe) is the central element in Hemoglobin, the protein in red blood cells. The iron atoms bind to oxygen molecules in the lungs and transport them to tissues throughout the body. This iron gives blood its red color. A lack of iron leads to anemia, reducing the blood's oxygen-carrying capacity.

Question 12

Which blood group is the Universal Donor?

Accepted Answer

Correct Answer: Group O Negative

Explanation: Blood Group O Negative (O-) is the Universal Donor. Red blood cells of O- type have no A, B, or Rh antigens on their surface. This means they can be safely transfused into a person with any other blood type without triggering an immune reaction. It is vital in emergency situations where blood type is unknown.

Question 13

What is the main function of the Ozone Layer?

Accepted Answer

Correct Answer: Absorb UV Rays

Explanation: The Ozone Layer (in the stratosphere) acts as Earth's sunscreen. It absorbs most of the Sun's harmful Ultraviolet (UV) radiation, specifically UV-B and UV-C. Without this layer, intense UV radiation would reach the surface, causing high rates of skin cancer, cataracts, and severe damage to crops and marine ecosystems.

Question 14

Which is the largest bone in the human body?

Accepted Answer

Correct Answer: Femur

Explanation: The Femur (thigh bone) is the largest, longest, and strongest bone in the human body. It runs from the hip to the knee. It supports the weight of the upper body and withstands the forces generated during walking, running, and jumping. A broken femur is a serious injury requiring significant force.

Question 15

Which gas is known as 'Marsh Gas'?

Accepted Answer

Correct Answer: Methane

Explanation: Methane (CH4) is known as Marsh Gas because it is naturally produced in marshes, swamps, and bogs. It is formed by the anaerobic bacterial decomposition of plant and animal matter under water. Bubbles of methane often rise to the surface in these areas. It is flammable and a potent greenhouse gas.

Question 16

The study of Coins is called:

Accepted Answer

Correct Answer: Numismatics

Explanation: Numismatics is the study or collection of currency, including coins, tokens, paper money, and related objects. Numismatists study the physical properties, production technology, and historical context of money. It provides valuable insights into the history, economy, and politics of ancient civilizations.

Question 17

Which lens is used to correct Short-sightedness (Myopia)?

Accepted Answer

Correct Answer: Concave Lens

Explanation: A Concave Lens is used to correct Myopia (short-sightedness). In myopia, light focuses in front of the retina, making distant objects blurry. A concave lens diverges the incoming light rays before they enter the eye, pushing the focal point back onto the retina, allowing for clear distance vision.

Question 18

What is the boiling point of heavy water?

Accepted Answer

Correct Answer: 101.4°C

Explanation: The boiling point of Heavy Water (D2O) is slightly higher than normal water, at 101.4°C (214.5°F). This is because deuterium (heavy hydrogen) makes the water molecules heavier and the bonds slightly stronger, requiring more energy (heat) to break them and turn the liquid into gas.

Question 19

Which part of the plant conducts water?

Accepted Answer

Correct Answer: Xylem

Explanation: Xylem is the vascular tissue in plants responsible for the upward transport of water and dissolved minerals from the roots to the stems and leaves. It is composed of hollow, tube-like cells. Phloem, on the other hand, transports food (sugars) made in the leaves to other parts of the plant.

Question 20

Which organism is called the 'Ship of the Desert'?

Accepted Answer

Correct Answer: Camel

Explanation: The Camel is called the Ship of the Desert because it is perfectly adapted to survive in harsh desert conditions. It has broad, padded feet to walk on sand without sinking, humps to store fat (energy), and can survive for days without water. Its long eyelashes and closing nostrils protect it from sandstorms.

Everyday Science MCQs