Chandrayaan-2, launched by the Indian Space Research Organisation (ISRO) on 22 July 2019, was designed to explore the South Pole region of the Moon. This area is of great scientific interest because it is permanently shadowed and may contain water ice and other valuable minerals. The mission included an orbiter, a lander (Vikram), and a rover (Pragyan), making it India’s first attempt at a soft landing on the lunar surface near the south pole.

Other options (for context)

• Moon North Pole: Not the target area of Chandrayaan-2.
• Moon North-West part: Incorrect — Chandrayaan-2 focused specifically on the South Pole.
• Unexplored part of the Moon: Partly true, but specifically, the unexplored South Pole region was chosen.

Explanation: Chlorofluorocarbons (CFCs) are the gases responsible for the depletion of the ozone layer. When released into the atmosphere, CFCs break down under ultraviolet (UV) radiation, releasing chlorine atoms that destroy ozone molecules (O₃), leading to thinning of the ozone layer and increased UV radiation reaching the Earth.

Helium is used instead of nitrogen in the breathing mixture for deep-sea divers. At high pressures underwater, nitrogen can dissolve in blood and cause nitrogen narcosis or “rapture of the deep.” Helium, being inert and less soluble in blood, prevents this condition and makes breathing easier under pressure.

• Argon, Xenon, Krypton: Inert gases but not suitable due to higher density and narcotic effects.

The Yellow Revolution in India refers to the significant increase in the production of oilseeds. It was initiated to make India self-sufficient in edible oils such as mustard, sunflower, groundnut, and soybean oils. The revolution gained momentum under the Technology Mission on Oilseeds (TMO) launched in the 1980s. The key figure associated with the Yellow Revolution is Sam Pitroda.

Other options (for context)

• Cereals: Their production growth is linked with the Green Revolution.
• Milk: Related to the White Revolution led by Dr. Verghese Kurien.
• None of these: Incorrect — the Yellow Revolution specifically concerns oilseeds.

Explanation: A transformer is an electrical device used to increase (step-up) or decrease (step-down) the voltage of alternating current (A.C.). It works on the principle of electromagnetic induction and functions only with A.C., not with D.C. A transformer consists of two coils—primary and secondary—wound around a soft iron core. The voltage ratio between these coils depends on the number of turns in each winding. Transformers are used in power transmission, distribution, and electronic devices to regulate voltage levels efficiently.

Brown is not seen in a rainbow. A natural rainbow displays seven distinct colours — Violet, Indigo, Blue, Green, Yellow, Orange, and Red (VIBGYOR). These colours appear due to the dispersion of sunlight by water droplets in the atmosphere, but brown is not part of the visible spectrum formed by dispersion.

• Yellow, Green, Red: All are part of the seven colours of the rainbow.

Explanation: The terms Dolby B and Dolby C refer to noise reduction circuits used in tape recorders and sound systems. These technologies reduce background hiss and unwanted noise during playback and recording, thereby improving the overall sound quality.