Everyday Science

Pressure can be measured in various units including Barr (likely intended as Bar), Torr, and Pascal. Therefore, all the options listed are valid units of pressure.

Alpha rays (alpha particles) cause maximum biological damage because they have high ionizing power and can cause severe damage to cells and tissues if ingested or inhaled, despite their low penetration ability. Gamma rays and beta rays penetrate more but cause less localized damage, and microwaves are non-ionizing and cause minimal biological damage.

The Summer solstice in the Northern Hemisphere occurs around June 21 each year, marking the longest day and the official start of summer. The other dates correspond to different astronomical events: July 21 is not a solstice or equinox, December 22 is the Winter solstice, and March 22 is near the Spring equinox.

Selenology is the scientific study of the Moon. The term derives from 'Selene,' the Greek goddess of the Moon, making option C the correct answer.

A velometer is an instrument used to measure the speed of air or wind. It is commonly used in meteorology and ventilation studies.

Milk is generally considered a balanced diet but is known to lack sufficient iron and vitamin C, which are essential nutrients not abundantly found in milk.

Chili peppers are rich in Vitamin C, which is important for immune function and skin health. Therefore, the correct answer is Vitamin C.

Sound is a mechanical wave that requires a medium (like air, water, or solids) to travel through, so it cannot pass through a vacuum. Light and other forms of electromagnetic radiation can travel through a vacuum.

Dates are botanically classified as true fruits; specifically, they are drupes (stone fruits) that develop from a single ovary and have a fleshy outer layer with a hard inner pit surrounding the seed. Apples, grapes, and plums are also true fruits but belong to different categories: apples are pomes, grapes are true berries, and plums are drupes. Therefore, all options are true fruits, but grapes are true berries, not drupes or pomes like the others. Since the question asks which is not a true fruit, and all listed are true fruits, the question is ambiguous. However, grapes are true fruits (berries), so the original answer 'Dates are not true fruits' is incorrect. The best correction is to clarify that all options are true fruits, and none is 'not a true fruit.'

As altitude increases, the air pressure decreases, causing the air to become thinner (less dense). Therefore, 'Thinner' is the correct description of air higher in the atmosphere.