science & technology Online Quiz - 427

Chlorine's symbol is Cl. Option A (Ch) is a common mistake students make. Si represents Silicon, and Tn is not a valid element symbol. Remember halogens follow specific naming patterns.

Iron's symbol is Fe from its Latin name 'Ferrum'. Option A (Ir) is actually Iridium. Io and In are not correct - In is Indium. This is one of several elements where the symbol doesn't match the English name.

Fluorine's symbol is simply F, one of the few single-letter element symbols along with H, B, C, N, O, etc. Options A and B (Fo, Fu) are incorrect guesses, and At is Astatine.

Hydrogen's symbol is H, the simplest and lightest element. Option A (T) is not a valid element symbol. Hn and Hd are incorrect combinations. Hydrogen is unique as the first element in the periodic table.

Platinum's symbol is Pt. Option A (Plat) might seem logical but chemical symbols are never three letters. Po is Polonium, and Gl is not a standard element symbol. Precious metals often have unique symbols.

Silver's symbol is Ag from its Latin name 'Argentum'. Option A (Si) is Silicon. Options C and D (Sl, Sv) are not valid element symbols. The term 'argent' meaning silver comes from this Latin root.

Phosphorus's symbol is simply P, like several other nonmetals (C, N, O, S, etc.). Option A (Ph) is not the official symbol. Po is Polonium, and Pr is Praseodymium. Common prefixes don't always match symbols.

In nuclear fission, the total mass of fragments is LESS than the parent mass due to mass-energy conversion (E=mc²). This 'missing mass' called mass defect is converted to kinetic energy of fragments and radiation. This is the principle behind nuclear power and weapons.

A four-stroke petrol engine operates on the Otto cycle, which consists of intake, compression, combustion (at constant volume), and exhaust strokes. The Diesel cycle differs by using constant pressure combustion, while the Rankine cycle applies to steam plants and the Carnot cycle is theoretical.

A four-stroke diesel engine operates on the Diesel cycle, which is characterized by constant pressure combustion (heat addition at constant pressure). Unlike the Otto cycle used in petrol engines, diesel engines compress air alone and then inject fuel which ignites spontaneously. Castor and jatropha cycles are not valid thermodynamic cycles.

Steam power plants operate on the Rankine cycle, which describes the working fluid's change from water to steam and back through the turbine, condenser, pump, and boiler. The Carnot cycle is an idealized theoretical cycle that cannot be practically implemented. Otto and Diesel cycles apply to internal combustion engines, not steam plants.

Jet engines and gas turbines operate on the Brayton cycle, which involves continuous compression, combustion at constant pressure, and expansion through the turbine. The Otto cycle is for reciprocating petrol engines, Carnot is theoretical, and Rankine applies to steam plants with phase change.

The Carnot cycle has the maximum theoretical efficiency among all heat engine cycles operating between the same two temperature limits, as stated by the Carnot theorem. Real cycles like Rankine, Brayton, and Otto have lower efficiencies due to irreversibilities, practical limitations, and finite heat transfer rates. The Carnot efficiency is given by 1 - T_cold/T_hot.

The Cyber-shot DSC-T77 is a digital camera model from Sony. Cyber-shot is Sony's brand for digital point-and-shoot cameras. The other options appear to be deliberate misspellings or variations of 'Sony' to test knowledge of the correct brand spelling.

Olympus is known for its 'Tough' series of rugged, waterproof, shockproof, and freezepoint compact cameras. These are designed for outdoor and adventure photography. Sony and Nikon make rugged cameras too, but 'Tough' is specifically an Olympus brand name. Option A is a misspelling.

Kodak's EasyShare series was a popular line of point-and-shoot digital cameras, and the Z980 model was indeed part of this Kodak product family. Sony, Samsung, and Olympus all made cameras but did not use the EasyShare branding.

Samsung produced the NX series of mirrorless cameras and interchangeable lens cameras between 2010-2016. Note that option B 'samsang' is a misspelling of Samsung. Nikon and Olympus had different camera series naming conventions.

The Nikon D90 was a groundbreaking DSLR camera released in 2008, notable for being the first DSLR with video recording capability. Sony and Samsung use different naming conventions, and Olympus does not have a D90 model.

Women's hearts typically beat 78-82 times per minute while men's hearts beat 70-72 times per minute. This is because women's hearts are generally smaller and must beat more often to pump the same amount of blood.

The human heart can generate enough pressure to squirt blood up to 30 feet. This is a well-documented factoid about the impressive pumping power of the human heart.