Everyday Science

Sunsets on Mars appear blue because the fine dust in the Martian atmosphere scatters sunlight differently than Earth's atmosphere, allowing blue light to penetrate and dominate during sunset.

Medium-sized kidney stones are commonly treated by lithotripsy, a procedure that uses shock waves to break stones into smaller pieces that can be passed naturally. Dialysis is unrelated to kidney stone removal, excretion is the natural process of elimination, and laser treatment is typically used for larger or more complex stones.

When a force is transmitted through a string, it is called tension. Weight is the force due to gravity, momentum is mass times velocity, and torque is a rotational force, so tension is the correct term here.

The length of the day is determined by Earth's rotation period and is not affected by atmospheric pollution levels. Therefore, an increase in atmospheric pollution does not change the length of the day.

Welding commonly uses gases like oxygen, acetylene, and argon. Oxygen and acetylene are used in oxy-acetylene welding, while argon is used as a shielding gas in processes like TIG welding. Hydrogen and nitrogen are not typical welding gases.

LPG (Liquefied Petroleum Gas) primarily consists of propane and butane, with methane present only in very small amounts or as an impurity. Therefore, option D correctly lists methane, butane, and propane as the main components, with butane and propane being the major constituents.

Heparin is a natural anticoagulant present in the blood that prevents coagulation inside the body, ensuring blood flows smoothly within vessels. Haemoglobin carries oxygen, fibrin forms clots, and plasma is the liquid component of blood but does not prevent coagulation by itself.

The chemical formula for water is H2O, which consists of two hydrogen atoms bonded to one oxygen atom. This is a fundamental and well-known fact in chemistry.

Gingivitis is an inflammation of the gums caused by bacterial infection, making the gums the part of the body affected by this disease.

Water is approximately 50 times more viscous than gases such as air. This means water resists flow much more than gases do, making option C correct.