Everyday Science — Past Papers — Part 2 MCQs with Explanations

Jupiter has the fastest rotation of all planets. It completing one rotation in about 9 hours 56 minutes . Additional information : Venus has the slowest rotation . It taking about 243 Earth days . Earth : ~ 24 hours Mars : ~ 24 hours 37 minutes.

The correct mathematical form is V = IR . Here V = voltage , I = current , R = resistance . Ohm’s law states that current is directly proportional to voltage when temperature is constant . It describes the relationship between voltage, current, and resistance .

Transpiration is the process by which plants lose water vapor through their leaves. Water mainly escapes through tiny pores called stomata present on the leaves. Transpiration helps in the movement of water and minerals from roots to other parts of the plant. It also helps in cooling the plant . Additional information : Absorption → Taking in water and minerals Respiration → Releasing energy from food Photosynthesis → Preparation of food

1 Megawatt (MW) = 1,000,000 watts (W) = 10⁶ W . The watt (W) is the SI unit of power . Additional information : 1 kilowatt (kW) = 10³ W 1 gigawatt (GW) = 10⁹ W 1 watt (W) = 1 W 1 milliwatt (mW) = 10⁻³ W

Photosynthesis is the process by which green plants prepare their food. Plants use sunlight, carbon dioxide , and water to produce glucose. Chlorophyll absorbs sunlight and helps in the process. Oxygen is released as a by-product.

Common salt is chemically known as sodium chloride (NaCl ). It is an ionic compound composed of sodium and chloride ions Representing a 1:1 ratio of sodium and chloride ions Formula : NaCl Melting point: 801 °C Density : 2.16 g/cm³ Boiling point: 1,465 °C Question updated on 11-02-2026

Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis . TB bacteria usually attack the lungs , but they can also affect other parts of the body. TB may affect the kidneys, spine, and brain . Tuberculosis (تپِ دق) is a serious infectious disease that commonly affects the lungs .

A mixture of salt and sand can be separated by dissolving it in water . Salt dissolves in water , while sand remains insoluble . The sand can then be separated by filtration . Finally, evaporation of the water recovers the dissolved salt.

Mycology is the branch of biology that studies fungi ( fungus ). It covers the structure, classification, growth, reproduction , and importance of fungi. Fungi include mushrooms, yeasts, and molds . Additional information : Entomology → Insects Mineralogy → Minerals Acoustics → Sound

The density of pure water at standard temperature ( 4°C ) is 1 g/cm³ or 1000 kg/m³. This value serves as a reference for measuring the density of other substances.

Gas molecules move freely in all directions because the particles are far apart . Gas particles have weak intermolecular forces and high kinetic energy . Additional information : Solids : Vibrate in fixed positions Liquids : Move/slide around each other

Hepta - is the prefix used to represent 7 carbon atoms . It is derived from the Greek word hepta , meaning seven . Additional information : 1 = Mono - 2 = Di - 3 = Tri - 4 = Tetra - 5 = Penta -

Sunlight, water, and carbon dioxide are the main requirements for photosynthesis . Green plants use chlorophyll to absorb sunlight. Additional information : Glucose is a product of photosynthesis. Oxygen is mainly released as a by-product .

Wavelength is the distance between two successive corresponding points of a wave, such as two crests. It can be measured in meters (m), centimeters (cm), and nanometers (nm). The SI unit of wavelength is meter ( m ). Nanometer (nm) is commonly used for very short wavelengths , especially in light. Conversions : 1 m = 100 cm 1 cm = 10⁻² m 1 nm = 10⁻⁹ m

Human bones are mainly composed of calcium and phosphate , primarily in the form of calcium phosphate . Calcium gives bones strength and hardness. Phosphate also plays an important role in maintaining strong bones and teeth. The major mineral in bone is hydroxyapatite , a calcium-phosphate compound .

Smog is a combination of smoke and fog . The word smog is formed from smoke + fog . It is a type of air pollution that reduces visibility and can harm human health . Smog is commonly associated with vehicle emissions and industrial pollutants.

Cell biology is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells . Also cellular biology or cytology

A step-up transformer increases the voltage. Output voltage > Input voltage It has more turns in the secondary coil than in the primary coil. It is used to increase voltage for long-distance power transmission .

Wilhelm Conrad Rontgen discovered X-rays He was discovered on 8 November 1895. He got the Nobel Prize i n Physics in 1901. Additional questions The penetrating power o f X-rays depends on their frequency Last updated 26-07-2026 by NA

Silviculture is the science and practice of establishing, growing , managing, and harvesting forest trees. It deals with the growth and development of forests . It aims to maintain healthy and productive forest resources. Additional information : Forestry : Science and management of forests and forest resources. Agriculture : Cultivation of crops and rearing of animals. Arboriculture : Cultivation and management of individual trees and shrubs.

In SONAR , the wavelength of the sound wave does not change simply because the submarine is farther away . Wavelength depends on the frequency of the sound and its speed in the medium , not on the distance traveled. Additional information : SONAR : Sound Navigation and Ranging It uses sound waves to detect and locate underwater objects .

Sericulture is the farming or rearing of silkworms for the production of silk. The most commonly cultivated silkworm is Bombyx mori . Silkworms feed mainly on mulberry leaves and produce silk fibers to form their cocoons . Additional information : Apiculture : Rearing of honeybees for honey and other products. Agriculture : Cultivation of crops and raising of animals. Pisciculture : Farming or breeding of fish.

Community consists of populations of different species living and interacting in the same area. Additional information : Population → members of the same species Ecosystem → community + non-living environment Biosphere → all ecosystems on Earth

A black box is a flight recorder used in aircraft . It records important flight data and cockpit audio . It helps investigators determine the causes of aircraft accidents or incidents . The two main types are Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR).

Watt (W) is the SI unit of power , while kilowatt (kW) is also a unit of power . 1 kilowatt = 1,000 watts. Power indicates the rate at which energy is used or transferred. Additional information : Kilowatt-hour (kWh) is a unit of electrical energy .

Polyethylene (PE) is one of the most widely used plastics in the world. Because it is lightweight , durable , chemically resistant , and relatively inexpensive . It is commonly used to make plastic bags, bottles, containers, packaging films , and household products. Polyethylene is produced from ethylene (ethene) through polymerization .

Arterial blood contains approximately 50 mL of CO₂ per 100 mL of blood. Most CO₂ is transported in the form of bicarbonate ions (HCO₃⁻).

The troposphere is the lowest layer of the atmosphere. Most weather phenomena occur in this layer . Clouds, rain, storms, and winds mainly occur here. It extends roughly 8–15 km above Earth’s surface. Additional information: Mesosphere: About 50–85 km; most meteors burn up here . Ionosphere: Region with many charged particles; important for radio communication and auroras. Stratosphere: About 12–50 km; contains the ozone layer.

WBCs survive for about 13–20 days, depending on the type. WBCs are also called Leukocytes . They protect the body against infections. They are produced in t he bone marrow. Important Note: The 13–20 days lifespan is not applicable to all WBCs; their lifespan varies according to type.

Nitrous oxide , commonly known as laughing gas. It is a colorless, non-flammable gas used in medicine. Nitrous oxide (N₂O) causes temporary laughing and relaxation . Additional information : Nitrous oxide was discovered by Joseph Priestley in 1772 .

The least count of a Vernier caliper is 0.1 mm (or 0.01 cm) . It is the smallest measurement that can be accurately read using the instrument. It is derived from the difference between one main scale reading and one Vernier scale reading. It is commonly used to accurately measure outside diameters of shafts, thicknesses of various parts, diameters of holes or rings, internal dimensions of hollow jobs, and depths of holes or steps.

Connective tissue provides support and structural strength to the body. Bone and cartilage are important connective tissues involved in skeletal support. It also connects, protects, and supports different body structures. It helps form the body's structural framework.

Carbohydrates make up approximately 2–10% of the cell membrane. They are mainly present on the outer surface of the plasma membrane . They are attached to proteins and lipids . They are forming glycoproteins and glycolipids . They help in cell recognition and communication .

Lactose = Glucose + Galactose Lactose is a disaccharide, meaning it contains two monosaccharide units . It is commonly known as milk sugar. Lactose is the main carbohydrate found in milk and dairy products.

Residual volume (RV) is the volume of air that remains in the lungs after maximum forced expiration. It cannot be voluntarily exhaled completely. It helps prevent the lungs from collapsing. It is different from normal tidal breathing .

Plasma is a component of extracellular fluid (ECF). It is the liquid portion of blood. Plasma is found within blood vessels . It contains water, proteins, electrolytes, nutrients , hormones, and waste products.

Calcitonin decreases blood calcium levels. It is a hormone produced by the C cells of the thyroid gland . It promotes calcium deposition in bones. It acts opposite to parathyroid hormone (PTH).

Chromosomes are present in the nucleus of eukaryotic cells. They are thread-like structures made of DNA and proteins . They carry genetic information . They help ensure the accurate distribution of genetic material during cell division.

The two strands of DNA run in opposite directions (5' to 3' on one strand and 3' to 5' on the other). This orientation is known as antiparallel . It is crucial for proper DNA replication and function.

The nucleus contains the cell’s genetic material (DNA). DNA carries hereditary information. The nucleus controls many cell activities. In prokaryotic cells (like bacteria) , DNA is not enclosed in a nucleus; it is found in the nucleoid region. Genetic material = DNA .