Science Olympiad : General Science MCQ set - 2
Q. What is the SI unit of pressure ?
Ans: Pascal
Explanation: The pascal (Pa) is the SI unit of pressure, defined as one newton acting on one square meter. It measures how much force is applied over a given area.
Q. Which element has the atomic number 1 ?
Ans: Hydrogen
Explanation:
Hydrogen, with atomic number 1, is the lightest and most abundant element in the universe. It contains one proton and is essential for forming stars and compounds like water.
Q. What organelle is known as the powerhouse of the cell ?
Ans: Mitochondria
Explanation: Mitochondria generate ATP, the cell’s main energy currency, through respiration. This energy powers vital biochemical processes, earning them the name “powerhouse of the cell.”
Q. What instrument detects earthquakes ?
Ans: Seismograph
Explanation: A seismograph records vibrations and seismic waves produced by earthquakes. It helps determine the earthquake’s magnitude, epicenter, and intensity.
Q. What is the function of ribosomes ?
Answer: Protein synthesis
Explanation: Ribosomes read genetic instructions and assemble amino acids into proteins. These proteins perform vital functions like enzyme activity, cell repair, and structural support.
Q. What process converts sugar into alcohol ?
Ans: Fermentation
Explanation: During fermentation, yeast breaks down sugars like glucose into alcohol (ethanol) and carbon dioxide in the absence of oxygen. This process is used in making wine, beer, and bread.
Q. Which gas is used in fire extinguishers ?
Ans: Carbon dioxide
Explanation: CO₂ extinguishers work by displacing oxygen and cooling the fuel, preventing combustion. CO₂ is effective for electrical and liquid fires.
Q. Which part of the nervous system controls reflex actions ?
Ans: Spinal cord
Explanation: Reflex actions are rapid, automatic responses controlled by the spinal cord, not the brain. This allows the body to react instantly to danger.
Q. Which body part helps maintain balance ?
Ans: Inner ear (semicircular canals)
Explanation: The semicircular canals in the inner ear detect head movement and send signals to the brain. This system helps maintain balance and coordination.
Q. What happens when an object floats in water ?
Ans: Buoyant force equals weight of displaced fluid
Explanation: According to Archimedes’ principle, an object floats when the upward buoyant force equals its weight. This balance allows the object to remain on the surface.
Q. Which blood group is a universal donor ?
Ans: O negative
Explanation: O-negative blood lacks A, B, and Rh antigens, so it can be safely given to all blood groups. It is vital in emergencies when blood type is unknown.
Q. Which metal is used to build airplanes ?
Ans: Aluminium
Explanation: Aluminium is lightweight, strong, corrosion-resistant, and easy to shape, making it ideal for aircraft bodies and wings, improving fuel efficiency and performance.
Q. What is the smallest bone in the human body ?
Ans: Stapes
Explanation: The stapes, located in the middle ear, helps transmit sound vibrations to the inner ear. It is only about 3 millimeters long.
Q. What device measures blood pressure ?
Ans: Sphygmomanometer
Explanation:
A sphygmomanometer measures systolic and diastolic blood pressure using a cuff, pump, and gauge. It helps monitor heart health and detect hypertension.
Q. Which gas makes up most of Earth's atmosphere ?
Ans: Nitrogen
Explanation: About 78% of Earth’s atmosphere is nitrogen. It is inert and helps dilute oxygen, reducing fire risk and supporting life processes.
Q. What is the function of the ozone layer ?
Ans: Protects Earth from UV radiation
Explanation: The ozone layer absorbs harmful ultraviolet rays from the Sun, preventing skin cancer, cataracts, and damage to ecosystems and materials on Earth.
Q. What is the chemical name for rust ?
Ans: Iron oxide
Explanation: Rust forms when iron reacts with oxygen and moisture, producing iron oxide. This reddish-brown compound weakens metal structures over time.
Q. What field of study covers plant life ?
Ans: Botany
Explanation: Botany is the branch of biology that studies plants, including their structure, growth, reproduction, classification, and ecological importance.
Q. What is the study of heredity called ?
Ans: Genetics
Explanation: Genetics examines how traits are passed from parents to offspring through genes. It explains inheritance, DNA structure, and genetic disorders.
Q. What is the powerhouse organelle of the cell ?
Ans: Mitochondria
Explanation: Mitochondria produce ATP energy through cellular respiration, powering essential functions like movement, growth, and repair—making them the cell’s energy center.