Tag: science & technology

Sound travels at approximately 343 meters per second in air at room temperature. For lightning striking 1 kilometer away, it takes approximately 3 seconds (1000 meters / 343 m/s ≈ 2.92 seconds) for the thunder to reach the observer. The 5-second rule is a common approximation where every 5 seconds equals approximately 1 mile.

Sounds with frequencies higher than 20,000 hertz are called ultrasonic. This is above the upper limit of human hearing. Infrasonic refers to sounds below 20 Hz, supersonic refers to objects moving faster than the speed of sound, and sonic boom is the shockwave created when an object breaks the sound barrier.

Vitamin D deficiency causes rickets, a condition where bones become soft and weak, especially in growing children. Colour blindness is genetic, wickets is a cricket term unrelated to nutrition, and nausea is a symptom not a deficiency syndrome.

Vitamin B12 deficiency causes megaloblastic anemia, where the body produces abnormally large red blood cells that can't function properly. Paralysis is not a direct result, spoon shaped nails indicate iron deficiency, and malaria is an infectious disease.

Vitamin A deficiency causes night blindness (difficulty seeing in low light conditions) and can lead to complete blindness if untreated. Colour blindness is a genetic condition, short sightedness is a refractive error, and myophia is not a recognized medical term.

HIV stands for Human Immunodeficiency Virus, the virus that attacks the body's immune system. The other options are made-up expansions. The virus specifically targets and weakens the immune system, leading to AIDS if untreated.

AIDS stands for Acquired Immune Deficiency Syndrome, the late stage of HIV infection where the immune system is severely damaged. Option B contains a typo (Sachet instead of Syndrome). The syndrome is acquired, not inherited, and involves immune deficiency.

Niacin (Vitamin B3) deficiency causes Pellagra, a disease characterized by diarrhea, dementia, and dermatitis. Rickets is caused by Vitamin D deficiency, while blindness can result from Vitamin A deficiency. Niacin is essential for energy metabolism and DNA repair.

Iron deficiency causes Anemia, a condition where the body lacks sufficient healthy red blood cells to carry adequate oxygen. Pneumonia, Malaria, and Dengue are infectious diseases not caused by nutritional deficiencies. Iron is crucial for hemoglobin production.