General Science and Technology Quiz

Casio introduced the first GPS watch in 1999 with the Casio GPS Pathfinder watch, which could determine location using satellite signals. This innovation allowed outdoor enthusiasts to track their position and navigate without separate GPS devices. Other companies followed later with GPS watches.

This statement is true. The average human skin hosts about 1 trillion microorganisms (bacteria, fungi, mites), while Earth's human population is approximately 8 billion. The skin microbiome is incredibly diverse and dense, with millions of microbes per square centimeter, especially in warm moist areas, making the total count vastly exceed all humans combined.

The statement is approximately correct. Average scalp hair count ranges from 100,000 to 150,000 strands, so the figure is accurate. Hair growth rate varies by individual (typically 0.3-0.4 inches monthly, totaling 3.6-4.8 inches annually), but 5 inches per year falls within normal variation. The statement captures the correct order of magnitude for both measurements, making it broadly true.

The statement is false as written. Astronauts actually become TALLER in space (up to 2-3 inches) due to spinal disc expansion in microgravity, not shorter. Upon return to Earth's gravity, this additional height is lost as the spine recompresses. The question reverses the actual phenomenon - they grow in space and shrink back to normal on Earth, not become shorter than they started.

This statement is false. While eyes reach near-adult size by childhood, ears and noses continue growing throughout life due to cartilage expansion and gravitational effects. This is why older adults appear to have larger noses and ears - they actually do grow slowly over decades. The only organ that truly stops growing early is the eye (specifically the eyeball), making the blanket statement incorrect.

Options A (H2O2 decomposition) and B (SO2Cl2 decomposition) are classic first-order reactions. Option D (2NO2 decomposition) is second-order because rate depends on [NO2]². Option C uses an incorrect formula (N2O2 is not stable; should be N2O5 for first-order decomposition), making it the 'not first-order reaction' by being chemically invalid.

RDX stands for 'Research Department Explosive' or 'Research Developed Explosive'. It's a powerful explosive compound widely used in military applications. The other options are fabricated expansions that don't correspond to the actual abbreviation.

Petrol (gasoline) has an energy density of approximately 45 MJ/kg, making it an efficient fuel for transportation. Option A (10 MJ/kg) is too low, option B (25 MJ/kg) is closer but still low, and option D (120 MJ/kg) is more characteristic of hydrogen or nuclear energy sources.

The flame velocity of a methane-air mixture is approximately 40 cm/s. This is a characteristic property of methane combustion in air at standard conditions. Option A (10 cm/s) is too slow, while options C and D (1 m/s and 4 m/s) are an order of magnitude too fast.

A typical candle releases energy at approximately 15 W. This represents the heat output from the combustion of wax. Options B, C, and D (45 W, 75 W, 150 W) are too high for a small candle flame.

A typical matchstick requires approximately 0.004 J (4 millijoules) of energy to ignite. This is the activation energy needed to initiate the combustion reaction of the match head. Options A, B, and C (0.4 J, 4 J, 0.04 J) are all too high for a match ignition.

The lower flammability limit (LFL) of hydrogen in air is 4% by volume. Below this concentration, the mixture is too lean to burn. Options A (0.4%), B (3%), and D (8%) are incorrect - 0.4% is too low, 3% is close but not the standard value, and 8% approaches the upper flammability limit.

Option D (NaCl + AgNO3 → NaNO3 + AgCl) is a precipitation/double displacement reaction, not a combustion process. Combustion involves rapid oxidation with heat and light (options A, B, C all show fuel + oxidizer → products). Option C shows reaction with fluorine, which is even more vigorous than typical combustion.

An oxy-acetylene torch typically achieves temperatures around 3000°C. This is due to the complete combustion of acetylene in pure oxygen. Options A (1000°C) and B (2000°C) are too low, while option D (5000°C) exceeds the theoretical flame temperature of acetylene-oxygen combustion.

A spark in a car engine typically releases energy for approximately 2 milliseconds. This brief duration is sufficient to ignite the fuel-air mixture. Options B (0.5 ms) is too short, while options C (10 ms) and D (25 ms) are too long for an efficient spark discharge.

Potatoes are one of the most commonly genetically engineered food crops, with genetically modified varieties like the Newleaf potato designed to resist pests and diseases. While tomatoes and wheat (for bread) can also be genetically modified, potatoes have the highest commercial adoption.

A transgenic crop contains genetic material from a different species, inserted through biotechnology techniques. Mutations (A) occur naturally or through induced radiation/chemicals without adding foreign genes. Traditional breeding (B) combines genes from the same species over generations.

GM foods can offer multiple benefits including extended shelf life through delayed ripening, enhanced nutritional profiles (like Golden Rice with Vitamin A), and reduced pesticide application due to built-in insect resistance. All three listed options are documented advantages of genetic modification in agriculture.

GM food concerns include allergic reactions from novel proteins not previously in food, genetic out-crossing where engineered traits spread to wild relatives through pollination, and herbicide-resistant weeds evolving due to selection pressure. Mutant species is a misleading term not based on documented scientific risks.

Atoms are mostly empty space because their mass is concentrated in a tiny nucleus, while electrons occupy orbitals that are vast relative to nuclear size. Even solid objects like granite are predominantly empty space at the atomic level.