Quantum Dots: Nanoscale Light Emitters
Quantum dots are man-made nanoscale semiconductor crystals that emit specific wavelengths of light when illuminated by UV light. Statement 1 is correct. The color of light emitted by a quantum dot is determined by its physical size, not solely by its chemical composition; smaller dots emit blue light, larger dots emit red light. Statement 2 is incorrect. Quantum dots find practical applications in high-definition television screens (QLED), targeted drug delivery, and solar cells, making Statement 3 correct. Therefore, the correct option is C) 1 and 3 only.
Nuclear Fusion: Key Facts and Misconceptions
Nuclear fusion involves combining two light atomic nuclei to form a single heavier nucleus. It releases significantly more energy per unit mass than nuclear fission. However, commercial fusion reactors do not require uranium or plutonium as primary fuel sources; they typically use isotopes of hydrogen like deuterium and tritium. Fusion does not produce long-lived, high-level radioactive waste. The incorrect statement is C) Commercial fusion reactors require uranium or plutonium as primary fuel sources.
Deepfakes and Generative Adversarial Networks
Deepfakes rely heavily on Generative Adversarial Networks (GANs), where two neural networks contest with each other: the Generator and the Discriminator. Statement 1 is correct. The Discriminator network detects flaws and identifies if the media is artificially created, not the Generator. Statement 2 is incorrect. Cryptographic watermarking is a method used to authenticate original media and detect deepfakes, making Statement 3 correct. Hence, the correct option is A) 1 and 3 only.
Solid-State Batteries: Next-Generation Energy Storage
Solid-state batteries replace the liquid or polymer gel electrolyte found in conventional lithium-ion batteries with a solid material, such as ceramics or solid polymers. This design offers higher energy density, faster charging, lower fire risk, and longer lifespan. Option B correctly describes this technology. Options A, C, and D describe other technologies.
Emerging Space Technologies: Correctly Matched Pairs
All three pairs are correctly matched. Kinetic Impactor is a planetary defense method tested by NASA's DART mission. Cryogenic Engine uses super-cooled liquefied gases like liquid oxygen and liquid hydrogen as fuel and oxidizer, as seen in ISRO's GSLV Mk III. Space Tug is a reusable spacecraft designed to transfer cargo or satellites between orbits. Therefore, the correct option is D) 1, 2, and 3.
