Heat and Thermodynamics MCQs 2026

In an adiabatic process, there is

1. Ano change in temperature✓
2. Bno change in pressure✓
3. Cno heat exchange with the surroundings✓
4. Dno change in internal energy✓

The SI unit of temperature is the

1. ACelsius✓
2. BFahrenheit✓
3. CRankine✓
4. DKelvin✓

Zero on the Kelvin scale, known as absolute zero, corresponds to approximately

1. A0 degrees Celsius✓
2. B-273.15 degrees Celsius✓
3. C100 degrees Celsius✓
4. D-100 degrees Celsius✓

The normal boiling point of water on the Celsius scale, at standard atmospheric pressure, is

1. A100 degrees Celsius✓
2. B0 degrees Celsius✓
3. C212 degrees Celsius✓
4. D373 degrees Celsius✓

The freezing point of water on the Fahrenheit scale is

1. A0 degrees Fahrenheit✓
2. B100 degrees Fahrenheit✓
3. C32 degrees Fahrenheit✓
4. D273 degrees Fahrenheit✓

Heat is best described as

1. Athe temperature of a body✓
2. Ba measure of average kinetic energy of molecules✓
3. Ca property stored permanently in a body✓
4. Denergy transferred between bodies due to a temperature difference✓

Temperature is best described as

1. Aa measure of the average kinetic energy of the molecules of a substance✓
2. Bthe total heat energy contained in a body✓
3. Cthe same as heat energy✓
4. Dalways constant for all substances✓

The amount of heat required to raise the temperature of a unit mass of a substance by one degree is called its

1. Alatent heat✓
2. Bspecific heat capacity✓
3. Cthermal conductivity✓
4. Dheat capacity of the container✓

The specific heat capacity of water is unusually

1. Avery low compared to most substances✓
2. Bequal to that of iron✓
3. Cequal to that of air✓
4. Dvery high compared to most common substances✓

The heat energy required to change a substance from solid to liquid, or liquid to gas, at constant temperature is called

1. Aspecific heat✓
2. Bsensible heat✓
3. Clatent heat✓
4. Dradiant heat✓

During a change of state, such as melting or boiling, the temperature of the substance

1. Aremains constant until the change is complete✓
2. Bincreases steadily✓
3. Cdecreases steadily✓
4. Dfluctuates randomly✓

The technique used to measure the heat exchanged in physical or chemical processes is called

1. Athermography✓
2. Bpyrometry✓
3. Cbarometry✓
4. Dcalorimetry✓

When a solid is heated, its dimensions generally

1. Adecrease✓
2. Bincrease, due to thermal expansion✓
3. Cremain exactly the same✓
4. Dbecome zero✓

The zeroth law of thermodynamics establishes the concept of

1. Aenergy conservation✓
2. Bentropy✓
3. Ctemperature and thermal equilibrium✓
4. Dabsolute zero only✓

The zeroth law of thermodynamics states that if two systems are each in thermal equilibrium with a third system, then

1. Athey are in thermal equilibrium with each other✓
2. Bthey must have equal masses✓
3. Cthey must have equal volumes✓
4. Dheat automatically flows between them✓

The first law of thermodynamics is essentially a statement of

1. Aincreasing entropy✓
2. Bconservation of energy✓
3. Czero heat transfer✓
4. Dabsolute zero being unreachable✓

According to the first law of thermodynamics, the change in internal energy of a system equals

1. Awork done by the system only✓
2. Bheat added only✓
3. Czero for any process✓
4. Dheat added to the system minus work done by the system✓

The second law of thermodynamics implies that

1. Aenergy can be created from nothing✓
2. Bheat always flows spontaneously from a colder body to a hotter one✓
3. Cheat cannot spontaneously flow from a colder body to a hotter one without external work✓
4. Dentropy of an isolated system always decreases✓

Entropy is best understood as a measure of

1. Athe disorder or randomness of a system✓
2. Bthe total heat content of a system✓
3. Cthe temperature of a system✓
4. Dthe pressure of a system✓

In an isothermal process, the

1. Apressure remains constant✓
2. Bvolume remains constant✓
3. Cheat exchange is zero✓
4. Dtemperature remains constant✓

In an isobaric process, the quantity that remains constant is

1. Avolume✓
2. Bpressure✓
3. Ctemperature✓
4. Dentropy✓

In an isochoric (isovolumetric) process, the quantity that remains constant is

1. Avolume✓
2. Bpressure✓
3. Ctemperature✓
4. Dheat✓

A Carnot engine is an idealized heat engine that operates on a cycle consisting of

1. Atwo isothermal and two isobaric processes✓
2. Bfour adiabatic processes✓
3. Ctwo isobaric and two isochoric processes✓
4. Dtwo isothermal and two adiabatic processes✓

The efficiency of a Carnot engine depends only on

1. Athe working substance used✓
2. Bthe size of the engine✓
3. Cthe temperatures of the hot and cold reservoirs✓
4. Dthe pressure of the gas✓

No real heat engine can be more efficient than a Carnot engine operating between the same two temperatures, a statement related to the

1. Azeroth law✓
2. Bsecond law of thermodynamics✓
3. Claw of conservation of mass✓
4. Dideal gas law✓

A refrigerator works by

1. Acreating cold energy from nothing✓
2. Bdestroying heat energy✓
3. Cconverting all heat into work✓
4. Dusing external work to transfer heat from a colder region to a hotter region✓

Boyle's law states that, at constant temperature, the pressure of a fixed mass of gas is

1. Ainversely proportional to its volume✓
2. Bdirectly proportional to its volume✓
3. Cindependent of its volume✓
4. Dproportional to the square of its volume✓

Charles's law states that, at constant pressure, the volume of a fixed mass of gas is

1. Ainversely proportional to its absolute temperature✓
2. Bindependent of temperature✓
3. Cdirectly proportional to its absolute temperature✓
4. Dproportional to the square of temperature✓

Gay-Lussac's law states that, at constant volume, the pressure of a fixed mass of gas is

1. Ainversely proportional to its absolute temperature✓
2. Bdirectly proportional to its absolute temperature✓
3. Cindependent of temperature✓
4. Dinversely proportional to volume✓

The ideal gas equation is generally written as

1. APV = nRT/2✓
2. BP + V = nRT✓
3. CPV^2 = nRT✓
4. DPV = nRT✓

Heat transfer through a solid medium, without bulk movement of the material, is called

1. Aconduction✓
2. Bconvection✓
3. Cradiation✓
4. Devaporation✓

Heat transfer through the actual bulk movement of a heated fluid, liquid or gas, is called

1. Aconduction✓
2. Bradiation✓
3. Cconvection✓
4. Dsublimation✓

Heat transfer that can occur even through a vacuum, via electromagnetic waves, is called

1. Aconduction✓
2. Bconvection✓
3. Cdiffusion✓
4. Dradiation✓

Metals are generally good conductors of heat because they contain

1. Atightly bound electrons✓
2. Bfree (mobile) electrons that readily transfer thermal energy✓
3. Cno electrons at all✓
4. Dvery heavy nuclei✓

A material with very low thermal conductivity, often used for insulation, is

1. Aglass wool or a similar insulating material✓
2. Bcopper✓
3. Csilver✓
4. Daluminum✓

The Stefan-Boltzmann law states that the power radiated by a black body per unit area is proportional to

1. Athe temperature✓
2. Bthe square of the temperature✓
3. Cthe fourth power of the absolute temperature✓
4. Dthe square root of the temperature✓

According to Wien's displacement law, as the temperature of a black body increases, the wavelength of peak emission

1. Aincreases✓
2. Bdecreases✓
3. Cremains constant✓
4. Dbecomes infinite✓

A perfect black body is defined as an object that

1. Areflects all radiation falling on it✓
2. Bemits no radiation at all✓
3. Cis always black in visible color✓
4. Dabsorbs all incident radiation and is also the best possible emitter✓

The triple point of water, at which solid, liquid, and gaseous water coexist in equilibrium, occurs at a unique

1. Atemperature and pressure✓
2. Bvolume only✓
3. Cdensity only✓
4. Dmass only✓

Sublimation refers to the direct change of state from

1. Aliquid to gas✓
2. Bgas to liquid✓
3. Csolid directly to gas, without passing through the liquid state✓
4. Dsolid to liquid✓

The change of a gas directly into a solid, without passing through the liquid state, is called

1. Aevaporation✓
2. Bcondensation✓
3. Cfusion✓
4. Ddeposition✓

Evaporation differs from boiling in that evaporation

1. Aoccurs only at the boiling point✓
2. Bcan occur at any temperature, from the liquid's surface only✓
3. Coccurs throughout the entire volume of liquid✓
4. Drequires no energy input✓

The process by which a vapor changes back into a liquid is called

1. Afusion✓
2. Bsublimation✓
3. Ccondensation✓
4. Dvaporization✓

The latent heat of vaporization of water at standard atmospheric pressure is approximately

1. A2260 kJ/kg✓
2. B334 kJ/kg✓
3. C4.2 kJ/kg✓
4. D100 kJ/kg✓

The latent heat of fusion of ice at 0 degrees Celsius is approximately

1. A2260 kJ/kg✓
2. B4.2 kJ/kg✓
3. C100 kJ/kg✓
4. D334 kJ/kg✓

A thermos flask (vacuum flask) minimizes heat loss mainly by reducing

1. Achemical reactions✓
2. Bconduction, convection, and radiation losses via a vacuum layer and reflective walls✓
3. Cthe specific heat of its contents✓
4. Dthe mass of the liquid stored✓

Thermal equilibrium between two bodies in contact is reached when

1. Aboth bodies attain the same temperature and no net heat flows between them✓
2. Bone body has zero temperature✓
3. Cboth bodies have the same mass✓
4. Dboth bodies have the same specific heat✓

An engine that converts heat energy into mechanical work by using the temperature difference between a hot source and a cold sink is called a

1. Arefrigerator✓
2. Bcalorimeter✓
3. Cheat engine✓
4. Dthermometer✓

No heat engine can convert 100% of the absorbed heat into useful work, a consequence of

1. Athe second law of thermodynamics✓
2. Bthe zeroth law of thermodynamics✓
3. CBoyle's law✓
4. DCharles's law✓

The specific heat capacity of water, approximately 4200 joules per kilogram per kelvin, means water

1. Aheats up and cools down very quickly compared to most substances✓
2. Brequires a relatively large amount of heat energy to change its temperature✓
3. Ccannot store any thermal energy✓
4. Dhas zero thermal conductivity✓