Tag: science & technology

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.