7th Class General Science Unit 10 Heat and Temperature MCQs (حرارت اور درجہ حرارت) | PAKMCQs

Atoms is correct because matter consists of tiny constituent particles called atoms, which bond together to form molecules.

Solid, liquid and gas is correct because the three fundamental classical states of matter are solid, liquid, and gas.

Only vibrate about mean position is correct because solid particles are locked in fixed lattice sites and only vibrate about their mean positions.

Particles flow is correct because fluids have weaker intermolecular forces which allow their particles to slide and flow freely.

Gases is correct because gas particles have negligible intermolecular attraction and move with complete freedom in all directions.

Attraction between them is correct because inter-particle potential energy arises from the intermolecular forces of attraction.

Gases is correct because gas molecules travel at high speeds, giving them the highest kinetic energy.

Solids is correct because particles in solids are restricted to localized vibrations, yielding the smallest kinetic energy.

Thermal energy is correct because the sum of internal kinetic and potential energies of all constituent particles is thermal energy.

Their motion is correct because kinetic energy is inherently the energy possessed by particles due to their motion.

Thermometer is correct because a thermometer is the clinical instrument used to measure thermal conditions and body temperature.

0°C and 100°C is correct because on the Celsius scale, pure water freezes at 0°C and boils at 100°C.

Falls below 0°C is correct because sub-zero winter temperatures in cold regions often drop below the freezing point of 0°C.

320 K is correct according to the textbook reference example illustrating a laboratory temperature of 320 K.

Temperature is correct because temperature quantifies the degree of hotness or coldness of an object.

Average kinetic energy of its particles is correct because macroscopic temperature is the direct measure of average molecular kinetic energy.

Thermometer is correct because the scientific device for measuring temperature is a thermometer.

Kelvin (K) is correct because the International System (SI) base unit for thermodynamic temperature is the kelvin (K).

Degree centigrade (°C) and degree fahrenheit (°F) is correct because Celsius and Fahrenheit are standard common temperature scales.

Scientific calculations is correct because the absolute Kelvin scale starts from absolute zero, making it essential for scientific and thermodynamic equations.

Clinical purposes is correct because clinical thermometers and medical body readings traditionally utilize degree Fahrenheit (°F).

Normal daily life temperatures (for weather) is correct because meteorological reports and everyday life monitor temperatures in degree Celsius (°C).

40°C is correct because temperature is an intensive property measuring average kinetic energy per particle, so it remains at 40°C.

All of the above is correct because the three standard thermometric scales are Kelvin, Celsius, and Fahrenheit.

Lower reference point and upper reference point is correct because calibrating a scale requires fixed lower and upper reference points.

Freezing point of water (melting point of ice) is correct because the standard lower fixed point is the ice point / freezing point of pure water.

Boiling point of water is correct because the standard upper fixed point is the steam point / boiling point of water at 1 atm.

Divisions of equal lengths is correct because thermometer calibration splits the interval into uniform, equal division lengths.

Difference between upper and lower reference points values is correct because: Divisions = Upper Point − Lower Point.

273 K is correct because pure ice melts/water freezes at 273 K on the thermodynamic Kelvin scale.

373 K is correct because water boils at 373 K at standard 1 atm atmospheric pressure.

100 equal divisions is correct because 373 K − 273 K equals exactly 100 equal divisions.

Celsius scale is correct because worldwide daily life and laboratory work most frequently use the Celsius (°C) scale.

0°C is correct because the lower reference point for water freezing on the Celsius scale is defined as 0°C.

100°C is correct because the upper reference point for water boiling on the Celsius scale is 100°C.

Change of one degree centigrade is correct because both Celsius and Kelvin scales share identical division increments of 100 intervals (Δ1 K = Δ1 °C).

32°F is correct because the lower reference point for water freezing on the Fahrenheit scale is 32°F.

212°F is correct because the upper reference point for water boiling on the Fahrenheit scale is 212°F.

180 equal divisions is correct because 212°F − 32°F yields exactly 180 equal divisions.

Less than is correct because 1°F corresponds to 5/9 (0.55) of a degree Celsius or Kelvin, making it a smaller interval.

T(K) = T(C) + 273 is correct because adding the 273.15 zero offset converts Celsius to Kelvin: T(K) = T(°C) + 273.

Temperature on Kelvin scale is correct because T(K) denotes the temperature value expressed on the Kelvin scale.

T(F) = 1.8 T(C) + 32 is correct because scaling by 9/5 (1.8) and adding 32 gives T(°F) = 1.8 × T(°C) + 32.

Temperature on Fahrenheit scale is correct because T(F) explicitly represents the thermodynamic value on the Fahrenheit scale.

37°C is correct because the physiological baseline core temperature of a healthy human body is 37°C.

310 K is correct because T(K) = 37 + 273 = 310 K.

66.6 is correct because multiplying 1.8 by 37 gives 66.6.

98.6 °F is correct because T(F) = 66.6 + 32 = 98.6 °F.

0 K is correct because the lower baseline limit of the Kelvin thermodynamic scale is 0 K.

Absolute zero is correct because 0 K represents absolute zero, the theoretical point where molecular thermal motion ceases.

-273°C is correct because 0 K corresponds to -273.15°C (approx. -273°C) on the Celsius scale.

Because molecules are always moving is correct because quantum zero-point energy ensures that molecules always possess residual motion.

It has only positive values in it is correct because starting at absolute zero (0 K), the Kelvin scale has no negative temperatures.

373K, 100°C, 212°F is correct because the normal boiling point of water is 373 K = 100°C = 212°F.

310K, 37°C, 98°F is correct because normal human core body temperature aligns at 310 K = 37°C = 98.6°F (approx. 98°F).

273K, 0°C, 32°F is correct because the freezing point of water across the three scales is 273 K = 0°C = 32°F.

0 K, -273°C, -459°F is correct because absolute zero equates to 0 K = -273°C = -459.67°F (approx. -459°F).

From hotter body to colder body is correct because thermal energy naturally transfers down a temperature gradient from a hotter body to a colder body.

Increase in kinetic energy of the water particles is correct because absorbed thermal energy increases the average kinetic energy of the particles.

It absorbs heat is correct because a temperature rise indicates that the object is absorbing thermal heat energy.

It loses heat is correct because a cooling body with falling temperature is losing thermal heat to its surroundings.

Greater amount of heat is correct because higher kinetic energy per particle generally gives a body a greater amount of internal thermal heat.

Greater temperature difference is correct because the rate of heat transfer is directly proportional to the temperature difference (ΔT) between objects.

Water currents move and steam flows out is correct because heating induces convection currents and evaporation steam.

Increases by heating is correct because thermal input increases molecular velocity and thus increases molecular kinetic energy.

Particles move faster is correct because adding heat increases average kinetic energy, causing particles to move faster.

Degree Fahrenheit is correct because clinical patient temperature monitoring standardly uses degree Fahrenheit (°F).

Amount of matter in it is correct because heat is an extensive property depending on both temperature and mass (amount of matter).

Half the amount of heat is correct because having half the mass at the identical temperature yields half the total thermal heat energy (Q = mcΔT).

Thermal equilibrium is correct because heat transfer stops when both bodies reach the same temperature in thermal equilibrium.

Coffee will lose heat and its temperature will decrease is correct because heat transfers from the hotter coffee to the colder milk, lowering the coffee's temperature.

Will absorb the heat and its temperature will increase is correct because cold milk absorbs heat from hot coffee, raising the milk's temperature.

Joule (J) is correct because the International System of Units (SI) unit for all forms of work and energy is the joule (J).

English physicist and mathematician is correct because James Prescott Joule was an English physicist and mathematician renowned for studying the mechanical equivalent of heat.

100J is correct because thermal heat is proportional to mass, so halving the volume cuts the heat content from 200J to 100J.

Thermal expansion is correct because the physical expansion of dimensions due to heating is thermal expansion.

Expand on heating and contract on cooling is correct because heating increases particle separation (expansion) while cooling reduces it (contraction).

Different for different states is correct because solids, liquids, and gases have different coefficients of thermal expansion.

Gases is correct because gases have the weakest intermolecular bonds and expand significantly more than liquids.

Solids is correct because liquids have looser binding forces than solids, so liquids expand more than solids.

Vibrate about mean position is correct because strong solid bonds hold particles in place while they vibrate about their mean positions.

Gain heat energy is correct because heating provides input thermal energy that particles absorb as heat energy.

Increases and vibrate with greater amplitude is correct because heated particles gain energy and vibrate with larger amplitude.

Gap between neighbouring atoms increases is correct because larger vibrational amplitudes force the mean inter-atomic spacing to expand.

It will lose heat to surroundings is correct because heat flows spontaneously from the hotter solid to the cooler surrounding air.

Will decrease is correct because losing heat lowers thermal energy, so particle vibrational K.E. and amplitude decrease.

Particles will come close to each other is correct because reduced vibrational motion allows neighbouring particles to draw closer together.

Vibrate a little with atoms in fixed positions is correct because unheated solid particles have small-amplitude vibrations around fixed sites.

All of the above is correct because thermal excitation increases vibrational K.E., expands inter-atomic spacing, and retains fixed lattice sites.

At large distance from each other is correct because fluid particles are at larger average distances from each other than packed solid lattices.

Start moving with greater K.E. and push each other is correct because heating speeds up fluid molecules, causing them to collide and push each other apart.

Liquid will lose heat to its surroundings is correct because the thermal gradient causes heat to flow from the liquid into the cooler air.

Will decrease and it will contract is correct because lower thermal motion allows molecules to draw closer, causing the liquid to contract in volume.

Expand on heating and contract on cooling is correct because heating expands intermolecular spacing while cooling causes thermal contraction.

In different ways in our daily life is correct because thermal expansion principles are utilized in thermometers, bimetallic strips, and engineering joints.

Metallic thermometer bulb and mercury is correct because body heat is conducted directly into the thermometer bulb and the mercury inside it.

Mercury rises in the capillary tube and stops after reaching thermal equilibrium is correct because thermal expansion ceases once thermal equilibrium is established.

Fahrenheit scale is correct because clinical patient body thermometers are calibrated primarily along the Fahrenheit (°F) scale.

Under hot water is correct because hot water heats the metal lid, causing it to expand faster than the glass and loosen.

Metal lid will expand and become loose is correct because metals have a high coefficient of thermal expansion, making the lid expand and loosen.

Gaps is correct because small expansion gaps are deliberately left between track segments to allow for hot weather expansion.

So it could expand and contract easily in summers without buckling is correct because without gaps, thermal expansion would cause the rails to warp and buckle.

Small sections is correct because dividing bridges into small sections with expansion joints accommodates seasonal thermal expansion.

Expand and contract easily during summer without any damage is correct because joints relieve internal stress by permitting free thermal expansion.

Tightly stretched wire is correct because winter contraction shortens wires, causing extreme tension in tightly stretched wires that leads to snapping.

From hot objects to cold objects is correct because second-law thermodynamics dictates heat flows from higher temperature to lower temperature.

All of the above is correct because heat transfers by three distinct mechanisms: conduction, convection, and radiation.

Conduction is correct because thermal energy travels through stationary solid metals via direct molecular conduction.

Conduction is correct because particle-to-particle lattice vibrational transfer of thermal energy defines conduction.

Hot part of the body is correct because thermal energy conducts internally from the hot part of the body to its colder regions.

Very close to each other is correct because solid particles are packed tightly very close to each other in fixed positions.

Begins to vibrate more energetically is correct because heating provides kinetic energy that makes particles oscillate vigorously.

Neighbouring particles is correct because vibrating particles collide with neighbouring particles to pass kinetic energy along the solid.

By the vibrations of particles is correct because conduction in solids occurs via inter-particle vibrations and lattice collisions.

They have free electrons is correct because delocalized free electrons move rapidly through metals transferring heat quickly.

Move fast and transfer the energy is correct because free electrons gain kinetic energy and drift rapidly across the lattice transferring energy.

Metals conduct heat fast and cooks the food easily is correct because high thermal conductivity allows rapid heat transfer to the food.

Poor conductors of heat (insulators) is correct because materials that resist thermal conduction are poor conductors or insulators.

Electrons are bound is correct because non-metals have tightly bound valence electrons that cannot move freely.

Solids is correct because close particle spacing in solids allows for much better conduction than liquids or gases.

Best insulators is correct because trapped still air has widely spaced molecules, functioning as one of the best thermal insulators.

Wool sweaters trap the air inside it is correct because wool fibers create tiny pockets that trap insulating air.

Air being insulator do not allow heat to conduct easily is correct because stationary air's low thermal conductivity blocks conductive heat loss.

Birds fluff out is correct because fluffing out feathers expands the space to trap a layer of insulating air.

Convection is correct because buoyant movement of warm fluids represents heat transfer by convection.

Convection is correct because the physical bulk movement of warmer molecules displacing colder ones is convection.

Fluids (liquids and gases) only is correct because only fluids permit the free macroscopic motion of particles needed for convection.

Expands and becomes less dense is correct because thermal expansion lowers water density, causing it to become buoyant and rise.

Cold water flows downward and hot water rises up is correct because less dense hot water rises while denser cold water sinks to take its place.

Convectional currents is correct because continuous cyclical loop circulation in heated fluid is a convection current.

Actual movement of particles from bottom to top is correct because fluid particles carry heat by physically migrating from hot bottom to cooler top.

Molecules gain greater kinetic energy, expands and becomes lighter is correct because ground heat warms the air layer, lowering its density.

Rises straight up is correct because lighter, low-density hot air is forced to rise upward by surrounding denser air.

Thermal is correct because a column of rising warm air created by surface convection is scientifically termed a thermal.

Fly for long time without fluttering their wings is correct because rising thermal updrafts give birds lift, allowing them to soar without flapping wings.

Eagles, hawks and vultures is correct because these large soaring birds excel at riding thermal air columns to gain altitude.

Convection is correct because differential heating of land and sea creates pressure gradients that drive convection breezes.

Land Breeze is correct because nighttime cooling makes land cooler than water, creating wind blowing from land towards the sea (Land Breeze).

Sea Breeze is correct because daytime solar heating warms land faster than sea, drawing cool wind from sea towards land (Sea Breeze).

Air is poor conductor and heated air rises up is correct because air blocks conduction and convective warm air rises toward the ceiling instead of sideways.

By radiation of heat is correct because electromagnetic radiation propagates through the vacuum of space without requiring any matter.

As no material is present for transfer of heat is correct because both conduction and convection strictly require material particles to transport energy.

Radiation is correct because the emission and propagation of thermal energy as electromagnetic waves is called radiation.

Matter is correct because radiative energy travels via photon fields without requiring intervening matter.

Infra-red (I.R.) is correct because thermal radiation is predominantly emitted and absorbed across the infra-red (I.R.) spectrum.

Radiation method is correct because solar radiation penetrates greenhouse glass and gets trapped inside as infrared thermal energy.

Roof is correct because the large surface area of the roof receives direct, continuous overhead solar radiation.

All three processes conduction, convection and radiation is correct because buildings gain heat through solar radiation, wall conduction, and air convection.

To lower transfer of heat and maintain temperature is correct because insulation minimizes heat ingress in summer and heat loss in winter.

With air trapped between ceiling and roof is correct because the dead air space between the layers acts as an effective thermal insulator.

Reflect most of heat energy is correct because light-coloured and reflective surfaces reflect incident solar radiation away from the roof.

So heat will take longer to conduct through it is correct because greater thickness provides higher thermal resistance and delays conduction.

Wall insulating panels is correct because modern facades use specialized wall insulating cladding panels to block thermal gain.

Air or argon gas is correct because a sealed gap of inert argon gas or dry air serves as an exceptional insulator.

Help to maintain the temperature inside the building is correct because insulation regulates indoor climate, maintaining comfortable interior temperatures.

Thermal energy is correct because the microscopic sum of all atomic potential and kinetic energies is defined as thermal energy.

Temperature of a body is correct because temperature measures the average kinetic energy of the particles in matter.

Kelvin scale, Celsius scale and Fahrenheit scale is correct because the three standard thermometric scales are Kelvin, Celsius, and Fahrenheit.

Heat is correct because heat is thermal energy in transit from high to low temperature regions.

Thermal equilibrium is correct because heat exchange ceases at zero temperature differential in thermal equilibrium.

Thermal expansion is correct because the expansion of material dimensions due to heating is thermal expansion.

Conduction, convection and radiation is correct because the three standard modes of heat transfer are conduction, convection, and radiation.

Heat is correct because the joule (J) is the SI unit measuring heat energy and work.

300 K is correct because T(K) = 27 + 273 = 300 K.

Metal is correct because metals have dense lattices and abundant free electrons that conduct heat rapidly.

273 K is correct because ice melts at 0°C which equals 273 K.

Thermal expansion is correct because a mercury thermometer operates by the thermal volumetric expansion of liquid mercury.

Air is correct because gases like air have widely spaced molecules, making air the worst conductor (best insulator).

Solids is correct because the closely packed lattice in solids provides the most efficient pathway for particle-to-particle conduction.

Insulators is correct because trapped dead air prevents heat conduction, making these materials excellent heat insulators.

Convection is correct because density differences drive buoyant fluid currents, transferring heat by convection.

Radiation only is correct because space is a vacuum that blocks conduction and convection, so solar energy travels via radiation only.