science & technology Online Quiz - 103

Mercury cannot form amalgams with iron because iron is immiscible with mercury - the two metals do not mix at all. Mercury readily forms amalgams with gold, silver, zinc, and many other metals, which is why mercury was historically used in gold and silver extraction. This is a fundamental chemical property tested in basic chemistry.

Sleeping sickness (African trypanosomiasis) is transmitted by the tsetse fly, which is found only in rural Africa. The disease is caused by parasites of the Trypanosoma brucei species and can be fatal if untreated. Filariasis is transmitted by mosquitoes, smallpox is viral and spreads person-to-person, and anthrax is bacterial from infected animals or spores.

Blood group O individuals can ONLY receive blood from other O group individuals because they have both anti-A and anti-B antibodies in their plasma. Receiving A or B blood would cause a dangerous transfusion reaction. While O is called the 'universal donor' (can give to anyone), they can only receive from other O donors. This is fundamental transfusion medicine.

A seismograph is the instrument used to measure and record the intensity of earthquakes. It detects and records the ground vibrations caused by seismic waves. A barometer measures atmospheric pressure, a hydrometer measures liquid density, and a polygraph is a lie detector. This is basic earth science knowledge.

Sharks have skeletons made entirely of cartilage rather than bone, which makes them lighter and more flexible. This characteristic classifies them as cartilaginous fish (Chondrichthyes), along with rays and skates. Most other fish have bony skeletons (Osteichthyes). Sharks do have teeth (multiple rows), gills for breathing, and a large liver, but no true bones.

Our solar system has 8 planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was reclassified as a dwarf planet in 2006 by the International Astronomical Union, reducing the count from 9 to 8. This is current astronomical knowledge taught in all basic science curricula.

Copernicus formulated the heliocentric model in the 16th century, proposing that Earth and other planets revolve around the Sun. This challenged the geocentric view that Earth was the center of the universe. Newton focused on gravity and motion laws, Dalton on atomic theory, and Einstein on relativity.

Despite being closer to the Sun than Venus, Mercury is not the hottest planet. Venus has an average surface temperature of about 462°C due to its thick carbon dioxide atmosphere that creates an extreme greenhouse effect. Mercury's average is around 167°C because it has no atmosphere to trap heat.

Halley's Comet is a short-period comet that orbits the Sun approximately every 76 years. This periodicity makes it visible from Earth roughly every 76 years, with its last appearance in 1986 and the next expected around 2061.

Cryogenic engines use liquefied gases stored at extremely low temperatures. The most common fuel combination is Liquid Hydrogen (fuel) and Liquid Oxygen (oxidizer). Liquid Nitrogen is not used as fuel in cryogenic engines, and Liquid Chlorine is toxic and not used in rocket propulsion.

Neutron stars are the densest and heaviest stellar objects (when comparing objects of similar size). They form from the collapsed core of massive stars and pack roughly 1.4-3 solar masses into a sphere only about 20 km in diameter. A neutron star of the same size as other star types would be exponentially heavier due to its extreme density.

ANUSAT (Anna University Satellite) was India's first student-made satellite, developed by students of Anna University, Chennai, and launched in 2009. INSAT is a communication satellite series by ISRO. STUDSAT was a later student satellite (2010). PRATHAM was IIT Bombay's student satellite (2016).

Human hair typically grows at approximately 0.5 to 0.7 inches per month, which converts to about 0.017 to 0.023 inches per day. The statement claims 0.01715 inches as a specific growth rate, which aligns with the lower end of this range and is biologically plausible.

The average human consumes significantly more than 3.25 pounds of food per day - typical estimates range from 3 to 5 pounds daily depending on body size and activity level. The statement presents this as an exact figure, which is not representative of average food consumption.

The human heart beats approximately 100,000 times per day on average, ranging from 60-100 beats per minute for a healthy adult at rest. The figure 1,03,689 falls within a reasonable range but appears as an unusually precise measurement rather than an average.

The average resting respiratory rate for adults is 12-20 breaths per minute, which would total approximately 17,000-29,000 breaths per day. The stated 23,045 falls within this physiological range, though the precision suggests specific measurement rather than average.

The human circulatory system is vast, with blood vessels totaling approximately 60,000-100,000 miles in length. The claimed figure of 16,80,000 miles (1.68 million) is significantly exaggerated beyond anatom reality. This appears to be a common myth or misrepresentation.

Human fingernails grow at approximately 0.1 inches (2.5 mm) per month, or about 0.003 inches per day. The stated figure of 0.00007 inches is far below the actual growth rate, making this statement false.