AFCAT Science and Technology 5 — Questions and Answers
Question 1: What is the principle behind a nuclear reactor generating electricity?
- Fusion of hydrogen nuclei releases heat to produce steam
- Fission of heavy nuclei releases heat that drives steam turbines (Correct answer)
- Chemical combustion of radioactive materials
- Beta decay of uranium directly produces electricity
Correct answer: Fission of heavy nuclei releases heat that drives steam turbines
Nuclear reactors use controlled fission of heavy nuclei (like U-235) to produce heat, which generates steam to drive turbines for electricity production.
Question 2: Which scientist formulated the three laws of planetary motion?
- Galileo Galilei
- Isaac Newton
- Johannes Kepler (Correct answer)
- Nicolaus Copernicus
Correct answer: Johannes Kepler
Johannes Kepler formulated three laws of planetary motion describing the elliptical orbits of planets around the Sun.
Question 3: Which gas is used in fire extinguishers to smother fires by displacing oxygen?
- Nitrogen
- Helium
- Carbon dioxide (Correct answer)
- Argon
Correct answer: Carbon dioxide
Carbon dioxide (CO₂) is commonly used in fire extinguishers because it displaces oxygen and does not conduct electricity or leave residue.
Question 4: What is the function of a transistor in electronic circuits?
- Stores electrical charge for later release
- Converts AC to DC current
- Amplifies or switches electronic signals (Correct answer)
- Resists current flow to control voltage
Correct answer: Amplifies or switches electronic signals
A transistor acts as an amplifier or electronic switch, forming the fundamental building block of modern electronic devices.
Question 5: Which Indian space mission was the first to successfully enter Mars orbit in its maiden attempt?
- Chandrayaan-1
- Chandrayaan-2
- Mangalyaan (Mars Orbiter Mission) (Correct answer)
- Aditya-L1
Correct answer: Mangalyaan (Mars Orbiter Mission)
Mangalyaan (Mars Orbiter Mission) launched in 2013 made India the first country to reach Mars orbit on its first attempt and at the lowest cost.
Question 6: What is the process by which plants convert sunlight into chemical energy stored as glucose?
- Respiration
- Transpiration
- Photosynthesis (Correct answer)
- Fermentation
Correct answer: Photosynthesis
Photosynthesis is the process by which plants use sunlight, water, and CO₂ to produce glucose and oxygen through chlorophyll-mediated reactions.
Question 7: Which material property describes its ability to return to original shape after deformation when stress is removed?
- Plasticity
- Ductility
- Elasticity (Correct answer)
- Malleability
Correct answer: Elasticity
Elasticity is the property of a material that allows it to recover its original shape and size after the deforming stress is removed.
AFCAT Science and Technology 5
What is the principle behind a nuclear reactor generating electricity?