GK Science

Mustard is an oilseed crop, not a cereal or grain crop. Rice, maize, and oat are all cereal grains (cereals belong to the grass family Poaceae), while mustard belongs to the Brassicaceae family and is cultivated for its seeds used in oil production.

Wheat is not a transplantation crop. It is a crop that is sown directly by broadcasting seeds or drilling. Tea, coffee, and coconut are transplantation crops where seedlings are first raised in nurseries and then transplanted to the main field.

Astronomy is the scientific study of celestial objects including the sun, stars, moon, and planets. It involves understanding their movements, properties, and the universe as a whole.

Botany is the scientific study of plants, including their structure, properties, and biochemical processes. Specifically, plant anatomy (the study of plant structure) is a branch of botany.

Energy is defined as the capacity to do work. The SI unit of energy is the Joule. Force causes acceleration (measured in Newtons). Power is the rate of doing work or using energy (Watts). The question tests the fundamental definition of energy.

Bleaching powder contains calcium hypochlorite, which releases chlorine when added to water. This process is called chlorination and kills harmful bacteria and microorganisms, making water safe for drinking. Convection is heat transfer, radiation uses electromagnetic waves, and electrolysis splits compounds using electricity.

Centrifugation uses centrifugal force to separate substances of different densities. Cream (fat) is less dense than skim milk, so it rises to the top and can be separated by spinning. Filtration separates solids from liquids using a filter. Crystallisation purifies dissolved solids from a solution.

Tungsten is used in electric bulb filaments because it has an extremely high melting point (3422°C) and resists sublimation at high temperatures. Iron would melt and oxidize too quickly. Platinum is expensive and not ideal. Cadmium is too soft and has a low melting point.

The ampere (A) is the SI unit of electric current, measuring the flow of electric charge. Ohm measures electrical resistance. Volt measures potential difference or voltage. Watt measures power (rate of energy transfer). Current is specifically measured in amperes.

Petroleum refining produces multiple useful products through fractional distillation. Kerosene is used as fuel and in lighting. Diesel powers engines. Paraffin wax is used in candles and packaging. Since all three are obtained from petroleum, 'All of these' is the correct answer.

The skeletal system provides structural support and enables movement through bones, joints, and muscles working together. The excretory system removes waste (kidneys, bladder). The circulatory system transports blood (heart, blood vessels). The respiratory system handles gas exchange (lungs). The skeleton is literally the framework that supports the body.

 The most abundant element in the universe is Nitrogen.

Combustion (burning) requires three things: fuel, heat, and oxygen. This is called the fire triangle. Petrol and kerosene are fuels, not the requirement for burning itself. Nitrogen does not support combustion (it's used in fire extinguishers). Oxygen is the essential reactant that enables burning.

Coal is formed from ancient plant matter that was compressed and heated over millions of years, giving it an organic origin. Sand is inorganic (silica). Sodium is a chemical element. Nylon is a synthetic polymer made from petrochemicals, so while carbon-based, it's not naturally organic in origin like coal.

Fossil fuels (coal, petroleum, natural gas) are formed from ancient buried organisms. Sunlight is a renewable energy source from nuclear fusion in the Sun, not a fossil fuel. Coal, petroleum, and natural gas are all classified as fossil fuels because they form from decomposed organic matter over geological time.

Milk and dairy products are rich in calcium and vitamin D, which are essential nutrients for building and maintaining strong bones and teeth. Pizza (depending on toppings), meat, fish, fruits, and vegetables provide other nutrients but dairy is specifically known for bone health due to its calcium content.

The brain is the central processing unit of the nervous system and receives all messages transmitted by nerve cells throughout the body. Neurons carry electrical signals from sensory receptors and other body parts to the brain for processing and response generation. The lungs, heart, and liver perform vital functions but do not serve as the central message-receiving center.

The kidney is part of the excretory/urinary system, not the digestive system. It filters blood and produces urine, whereas the digestive system (including liver, pancreas, and small intestine) breaks down and absorbs nutrients from food. The question correctly identifies kidney as the non-digestive component.

Sunlight is electromagnetic radiation, not a force. Push and pull are fundamental ways forces manifest, and gravity is a natural force that attracts objects with mass toward each other. Forces involve push or pull interactions that can cause acceleration, whereas sunlight is energy in the form of electromagnetic waves.

Burning a candle is a chemical change because wax reacts with oxygen to form new substances (carbon dioxide and water vapor). The other options involve physical changes - cutting cloth changes only shape, breaking glass changes only form, and chalk falling changes only position. In a chemical change, new substances with different properties are formed.

Marie and Pierre Curie are famous for their research on radioactivity and for discovering radium and polonium in 1898. Radium became the element most closely associated with their work and led to their Nobel Prize in Physics. While they also worked with uranium, radium was their groundbreaking discovery.

Hydrogen atoms are the smallest because hydrogen has the lowest atomic number (1), meaning it has only one proton and typically one electron. Helium has 2 protons and electrons, oxygen has 8, and uranium has 92. The size of an atom is primarily determined by its number of protons and electron shells.

The troposphere is the lowest layer of Earth's atmosphere, extending from the surface up to about 6-20 kilometers altitude. It contains approximately 75% of the atmosphere's mass and virtually all weather phenomena. The stratosphere, mesosphere, and ionosphere are progressively higher layers farther from Earth's surface.

Mango is a green plant that performs photosynthesis, containing chlorophyll and producing its own food. Fungus, mushroom, and mould belong to the Kingdom Fungi - they lack chlorophyll, cannot perform photosynthesis, and obtain nutrients by decomposing organic matter. Only mango is a true photosynthetic plant.