Physics questions and answers

Thermal Physics Questions MCQs with Answers

Thermal Physics questions Important MCQs with Answers for Technical Cadet Course, Army Education Officers, Army EME Officers. Join Pak Army, PAF or Navy with 100% best preparation of physics questions for initial tests.

The zeroth law of thermodynamics states that if two systems are in thermal equilibrium with a third system, then they are in ____________________ with each other.(Thermal equilibrium)

The first law of thermodynamics, also known as the law of ____________________, states that energy cannot be created or destroyed, only transferred or converted from one form to another.(Conservation of energy)

The second law of thermodynamics states that the total entropy of an isolated system always ____________________ or remains constant in a reversible process.(Increases)

The third law of thermodynamics states that as the temperature approaches absolute zero, the entropy of a system approaches ____________________.(Zero)

The first law of thermodynamics can be expressed mathematically as ΔU = Q – _______, where ΔU represents the change in internal energy, Q represents heat transfer, and W represents work done on or by the system.(W (work))

According to the first law of thermodynamics, if a system absorbs heat and does work on its surroundings, the change in internal energy will be ____________________. (Positive)

The second law of thermodynamics introduces the concept of ____________________, which is a measure of the disorder or randomness of a system. (Entropy)

The second law of thermodynamics states that heat flows spontaneously from a region of ____________________ temperature to a region of lower temperature. (Higher)

The second law of thermodynamics sets a limit on the maximum efficiency of ____________________ engines. (Heat)

The second law of thermodynamics predicts that natural processes tend to go in the direction of increasing ____________________ of the universe. (Entropy)

The _________ law of thermodynamics provides a reference point for measuring absolute temperatures by stating that the entropy of a perfect crystal at absolute zero is zero. (Third)

The first law of thermodynamics is a statement of the ____________________ of energy. (Conservation)

The second law of thermodynamics states that it is impossible to construct a device that operates in a _________ process and extracts heat from a single reservoir to produce work. (Reversible)

The second law of thermodynamics introduces the concept of ____________________ to quantify the direction of spontaneous processes. (Entropy)

The third law of thermodynamics states that it is impossible to reach the temperature of absolute zero through any ____________________ process. (Finite)

Heat is the energy transferred between objects due to a difference in _________. (Temperature)

Temperature is a measure of the average ____________________ of the particles in a substance. (Kinetic energy)

The SI unit of temperature is the ________. (Kelvin)

The transfer of heat through direct contact between particles of a substance is called ____________________.(Conduction)

The transfer of heat through the movement of fluid particles is called _________. (Convection)

The transfer of heat through electromagnetic waves is called ____________________. (Radiation)

The specific heat capacity of a substance is the amount of heat energy required to raise the temperature of one ____________________ of the substance by one degree Celsius. (Kilogram)

The equation Q = mcΔT relates heat transfer (Q) to mass (m), specific heat capacity (c), and ____________________ difference (ΔT). (Temperature)

The process of a substance changing from a solid to a liquid is called ____________. (Melting)

The process of a substance changing directly from a solid to a gas without going through the liquid phase is called ____________________. (Sublimation)

The freezing point of water on the Celsius scale is ____________________ degrees Celsius. (0)

The boiling point of water on the Celsius scale is ____________________ degrees Celsius. (100)

The Kelvin temperature scale is commonly used in ____________________ calculations. (Scientific)

Thermal Physics Questions with Answers: MCQs for Army with Answers

Soldiers can test their knowledge and understanding of thermal physics by answering the MCQs provided in “Thermal Physics Important MCQs for Army with Answers.”

The transfer of heat energy is always from an object with ____________________ temperature to an object with lower temperature. (Higher)

The ____________________ law of thermodynamics states that it is impossible to reach absolute zero temperature through any finite number of processes. (Third)

Thermal expansion is the tendency of a substance to change in ____________________ in response to a change in temperature. (Size or volume)

The coefficient of ____________________ expansion is a characteristic property of a material that quantifies its response to temperature changes. (Linear or volumetric)

The linear expansion coefficient measures the change in ____________________ per unit length per degree Celsius (or Kelvin) temperature change. (Length)

The volumetric expansion coefficient measures the change in ____________________ per unit volume per degree Celsius (or Kelvin) temperature change. (Volume)

An object will expand when its temperature ____________________, and contract when its temperature decreases. (Increases)

The ____________________ effect is the phenomenon of two different materials expanding or contracting at different rates when subjected to the same temperature change. (Bimetallic)

The ____________________ point of a material is the temperature at which it exhibits no expansion or contraction. (Zero or null)

The expansion of a solid material can be calculated using the equation ΔL = αL0ΔT, where ΔL is the change in length, α is the coefficient of linear expansion, L0 is the initial length, and ΔT is the change in ____________________. (Temperature)

The expansion of a liquid or gas can be calculated using the equation ΔV = βV0ΔT, where ΔV is the change in volume, β is the coefficient of ____________________ expansion, V0 is the initial volume, and ΔT is the change in temperature. (Volumetric)

The ____________________ bridge is a device used to measure small changes in length due to thermal expansion. (Wheatstone)

An ____________________ is a device that uses the differential expansion of metals to measure temperature changes. (Bimetallic strip)

The ____________________ is a temperature scale that is commonly used in scientific and engineering applications, where 0 K represents absolute zero. (Kelvin)

The ____________________ point of a substance is the temperature at which it changes from a liquid to a solid phase. (Freezing or Melting)

The ____________________ point of a substance is the temperature at which it changes from a liquid to a gas phase. (Boiling or Vaporization.)

The concept of thermal expansion is important in engineering applications such as ____________________ design and construction. (Structural or Architectural)

Heat transfer is the process of ____________________ of thermal energy between objects or systems due to a temperature difference. (Transfer or flow)

Conduction is the mode of heat transfer that occurs through ____________________ contact between particles or objects. (Direct or physical)

Convection is the mode of heat transfer that occurs through the ____________________ of fluid particles. (Movement or circulation)

Radiation is the mode of heat transfer that occurs through ____________________ electromagnetic waves. (Emission or transmission)

In conduction, heat flows from regions of ____________________ temperature to regions of lower temperature. (Higher or greater)

The ____________________ law of thermodynamics states that heat flows spontaneously from a region of higher temperature to a region of lower temperature. ( Second)

The rate of heat conduction through a material depends on its ____________________ conductivity. ( Thermal or heat)

The equation Q = kAΔT/Δx represents ____________________’s law of heat conduction, where Q is the heat flow, k is the thermal conductivity, A is the cross-sectional area, ΔT is the temperature difference, and Δx is the thickness of the material. (Fourier)

________________ is the process of heat transfer that occurs in fluids due to the movement of heated fluid rising and cooler fluid sinking. (Natural convection)

________________ is the process of heat transfer that occurs in fluids due to the use of fans or pumps to enhance fluid movement. (Forced convection)

The ____________________ effect is the phenomenon where a fluid flowing past a solid surface experiences a decrease in pressure and an increase in velocity. (Bernoulli)

Physics Questions Important MCQs for Pak Navy with Answers

Thermal Physics Important MCQs for Pak Navy with Answers for PN Cadets, Navy Operation Branch, Navy Education Branch, Navy Supply Branch, Mechanical Engineering Branch, Navy Ordnance Branch

________________ is the transfer of heat energy in the form of electromagnetic waves, which does not require a medium. (Radiation)

The ____________________ law of thermodynamics states that the total entropy of an isolated system always increases or remains constant in a spontaneous process. (Second)

The ____________________ law of thermodynamics provides a reference point for measuring absolute temperatures by stating that the entropy of a perfect crystal at absolute zero is zero. (Third)

The rate of radiant heat transfer is influenced by factors such as the ____________________ of the radiating surface, the temperature difference, and the distance between objects. (Emissivity or emissive power)

Entropy is a thermodynamic property that measures the ____________________ or disorder of a system. (Randomness or degree of disorder)

The change in entropy of a system can be calculated as ΔS = Q/T, where ΔS is the change in entropy, Q is the heat transfer, and T is the ____________________ at which the heat transfer occurs. (Temperature)

The second law of thermodynamics states that the total entropy of an isolated system always ____________________ or remains constant in a reversible process. (Increases)

The ____________________ law of thermodynamics states that it is impossible to reach absolute zero temperature through any finite number of processes. (Third)

The Carnot cycle is a theoretical thermodynamic cycle that consists of two____________________ processes and two reversible adiabatic processes. (Isothermal)

The Carnot cycle operates between two thermal reservoirs, a high-temperature reservoir (TH) and a low-temperature reservoir (TL), and is the most efficient ____________________ cycle. (Heat engine)

The efficiency of a Carnot engine is given by the equation ____________________ = 1 – (TL/TH), where TL is the low-temperature reservoir and TH is the high-temperature reservoir. (Efficiency)

The efficiency of a Carnot engine is ____________________ to the temperature difference between the hot and cold reservoirs. (Proportional)

The Carnot refrigerator operates in a reverse manner compared to the Carnot engine, transferring heat from a ____________________ reservoir to a high-temperature reservoir. (Low-temperature or cold)

The Carnot cycle is a ____________________ cycle, meaning that it can be reversed to act as either an engine or a refrigerator. (Reversible or reversible heat engine)

The efficiency of a Carnot engine is ____________________ than the efficiency of any other heat engine operating between the same two temperatures. (Higher or maximum)

The Carnot theorem states that no heat engine can be more ____________________ than a Carnot engine operating between the same two reservoirs. (Efficient)

The Carnot cycle is an idealized cycle that serves as a ____________________ for real-world heat engines and refrigerators. (Model or theoretical framework)

The Carnot cycle is characterized by ____________________ adiabatic and reversible processes, ensuring maximum efficiency. (Isothermal)

The Carnot cycle provides a ____________________ limit for the efficiency of heat engines, known as the Carnot efficiency. (Theoretical or maximum)

Thermal equilibrium is a state in which two or more objects are at the same ____________________. (Temperature)

In thermal equilibrium, there is no ____________________ of heat between objects. (Net flow or transfer)

The ____________________ law of thermodynamics states that if two systems are separately in thermal equilibrium with a third system, they are in thermal equilibrium with each other. (Zeroth)

A heat engine is a device that converts ____________________ energy into mechanical work. (Heat or thermal)

The efficiency of a heat engine is defined as the ratio of ____________________ work output to the heat input. (Useful or net)

The ____________________ law of thermodynamics states that no heat engine can have an efficiency of 100%. (Second)

The efficiency of a heat engine is given by the equation ____________________ = (W/QH) x 100%, where W is the work output and QH is the heat input. (Efficiency)

The ____________________ law of thermodynamics states that as a system approaches absolute zero, its entropy approaches a minimum value. (Third)

Thermal Physics Multiple Choice Questions and Answers

Thermal Physics Multiple Choice Questions and Answers for PAF Logistics Branch, PAF GD Pilot, PAF Aeronautical Engineering, PAF Air Defence Branch, PAF Admin & Special Duty Branch.

The ____________________ law of thermodynamics states that the entropy of an isolated system always increases in a spontaneous process. (Second)

The ____________________ cycle is a commonly used idealized model for heat engines, consisting of four processes: isentropic compression, constant-volume heat addition, isentropic expansion, and constant-volume heat rejection. (Otto)

The ____________________ cycle is a thermodynamic cycle used in most automobile engines. (Otto.)

The ____________________ cycle is a commonly used idealized model for gas turbines, consisting of four processes: isentropic compression, constant-pressure heat addition, isentropic expansion, and constant-pressure heat rejection. (Brayton)

The ____________________ cycle is commonly used in aircraft jet engines and power plants. (Brayton)

The ____________________ cycle is a thermodynamic cycle used in refrigeration and air conditioning systems. (Vapor-compression)

The ____________________ cycle is commonly used in household refrigerators, air conditioners, and heat pumps. (Vapor-compression)

Conduction is the mode of heat transfer that occurs in solids due to the ____________________ of thermal energy between neighboring particles. (Collision or transfer)

In conduction, heat flows from regions of ____________________ temperature to regions of lower temperature. (Higher or greater)

The thermal conductivity of a material determines its ability to conduct ____________________. (Heat or thermal energy)

The rate of heat conduction through a material is proportional to the cross-sectional area and the ____________________ difference across the material. (Temperature or temperature gradient)

The ____________________ law of heat conduction states that the rate of heat flow through a material is directly proportional to the cross-sectional area and the temperature difference, and inversely proportional to the thickness. (Fourier’s or Fourier’s law)

The thermal conductivity of a material depends on its ____________________ and its physical properties, such as density and specific heat capacity. (Composition or structure)

The ____________________ is a measure of how well a material can resist the flow of heat. (Thermal resistance)

The ____________________ effect is the phenomenon where heat flows more readily along the length of an object compared to the flow across its width. (Anisotropic or directional)

____________________ is a process used to reduce heat transfer by introducing insulating materials with low thermal conductivity. (Insulation or thermal insulation)

The ____________________ coefficient is a measure of the ability of a material to store heat energy. (Thermal diffusivity)

The ____________________ point is the temperature at which a material loses its ability to conduct heat effectively. (Melting or melting point)

The ____________________ effect is the phenomenon where the thermal conductivity of a material decreases as its temperature decreases. (Thermal conductivity reduction or thermal conductivity decrease)

The ____________________ is a measurement unit used to quantify the resistance to heat flow, equal to one watt per square meter per degree Celsius. (R-value)

The ____________________ effect is the phenomenon where the thermal conductivity of a material increases as its temperature increases.(Thermal conductivity enhancement or thermal conductivity increase)

In materials with high ____________________, such as metals, heat transfer occurs primarily through conduction. ( Thermal conductivity.)

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  • Free Thermal Physics Important MCQs PDF (Download)
  • Thermal Physics Important MCQs for Army with Answers PDF (Download)
  • PAF Physics MCQs PDF (Download)

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