Heat Transfer Mechanisms

Conductance of heat is the most essential property of a substance for a cooking vessel. Due to this property, vessel heats quickly.

It is wrong, friction is independent of area.

It is correct. Animals in which the body temperature varies according to surrounding environment are called cold-blooded or poikilothermal animals.

Cryogenics is the branch of physics concerned with the production and behavior of materials at extremely low temperatures, typically below -150°C. It has applications in preserving biological materials, superconductivity research, and rocket fuel storage.

Heat from the Sun reaches Earth through radiation alone - electromagnetic waves that can travel through the vacuum of space. Conduction requires direct contact between materials, which is impossible across empty space. Convection requires a medium (fluid/gas) to circulate, which doesn't exist in the vacuum between Sun and Earth. Therefore, radiation is the sole mode of heat transfer from the Sun to our planet.

A pyrometer measures temperature by detecting the thermal radiation emitted by an object. It works on Stefan-Boltzmann principle where emitted radiation is proportional to the fourth power of absolute temperature. Unlike contact thermometers, pyrometers enable non-contact measurement of extremely high temperatures (1000°C+), making them ideal for furnaces, molten metals, and applications where physical contact would damage the sensor. Options A, B, and C refer to thermocouples, conduction, and convection respectively, which are contact-based measurement methods.

Two thin shirts keep us warmer than one thick shirt because the air layer trapped between them acts as an insulator. Air is a poor conductor of heat, so this trapped layer reduces heat loss from the body more effectively than a single thick shirt would.

Copper does not react with steam because it is one of the most non-reactive metals.

Radiation is the form of heat transfer that can occur in the absence of a medium. Thus, it is possible to transfer heat in vacuum through the process of radiation.

Electrons produce fluorescence when they strike crystals, minerals and salts.

Iron is a metal with high thermal conductivity, meaning it transfers heat quickly through its structure. Wood is an insulator with much lower thermal conductivity, so it absorbs and transfers heat more slowly. This is why metals feel hot quickly when placed in sunlight.

Water has the highest specific heat capacity among common substances (approximately 4.18 J/g°C). This means water can absorb more heat energy per unit mass before its temperature rises significantly. Metals like iron (0.45 J/g°C) and gold (0.13 J/g°C) have much lower heat capacities. Benzene has a moderate heat capacity (around 1.8 J/g°C).

Water has much higher specific heat capacity than land, meaning it takes more energy to change its temperature. This causes oceans to heat and cool slowly compared to land. Viscosity affects fluid flow, not thermal response rate. Transparency does not significantly affect heating/cooling rates.

Thermal capacity, is the measurable physical quantity that characterizes the amount of heat required to change a substance's temperature by a given amount. In the International System of Units (SI), heat capacity is expressed in units of joule(s) (J) per kelvin (K).

Glass allows shortwave solar radiation to pass through but traps longwave infrared radiation, creating heat buildup. This is the same principle as the greenhouse effect where gases like CO2 trap heat in the atmosphere.