Free Thermal Equilibrium and Heat MCQs with Answers

• A. they have the same mass
• B. they are at the same temperature, so there is no net flow of heat between them
• C. they contain the same amount of heat
• D. they are made of the same material

Explanation: Temperature is what decides the direction of heat flow, so equal temperatures mean no net transfer even if the two bodies hold very…

• A. the total energy contained in a body
• B. the temperature of a body
• C. energy in transit from a hotter body to a cooler one because of the temperature difference
• D. a fluid that flows between bodies

Explanation: Heat is a process word: it names energy while it is being transferred, which is why a body is said to contain internal energy rather than…

• A. 0 degrees Celsius
• B. minus 100 degrees Celsius
• C. minus 273 degrees Celsius
• D. minus 373 degrees Celsius

Explanation: Zero kelvin is minus 273.15 degrees Celsius, the temperature at which the pressure of an ideal gas would extrapolate to zero and molecular…

• A. mass times specific heat capacity times temperature change
• B. mass divided by specific heat capacity
• C. specific heat capacity times temperature change only
• D. mass times temperature change only

Explanation: The formula Q equals mc times delta T holds whenever there is no change of state, and specific heat capacity is the heat needed to raise…

• A. raises its temperature steadily
• B. breaks the bonds of the solid structure without changing the temperature
• C. is lost to the surroundings entirely
• D. lowers the internal energy

Explanation: The latent heat of fusion goes entirely into overcoming the forces holding the lattice, so the temperature stays at the melting point…

• A. the block with more mass becomes hotter
• B. both reach the same temperature
• C. both reach the same internal energy
• D. the hotter block loses all its energy

Explanation: Transfer continues only while a temperature difference exists, so equilibrium is reached when the temperatures match, not when the…

• A. 760 torr
• B. 760 mmHg
• C. 101.3 kPa
• D. all of the above

Explanation: The standard atmospheric pressure is 1 atm = 760 torr = 760 mmHg = 101.3 kPa.

• A. Base quantities
• B. Derived quantities
• C. Prefixes
• D. Quartile quantities

Explanation: Length, mass, time, luminous intensity and amount of substance are SI base quantities because their units are fundamental and are not…

• A. ΔL = αLΔT
• B. ΔL/LΔT
• C. LΔT/ΔL
• D. αLΔT-ΔL

Explanation: From linear expansion, ΔL = αLΔT, so the coefficient is α = ΔL/(LΔT), with unit K^-1.

• A. Decreases
• B. Increases
• C. Remains same
• D. Becomes Zero

Explanation: A liquid boils when its vapour pressure equals the surrounding pressure.

• A. momentum
• B. mass
• C. velocity
• D. kinetic energy

Explanation: The mean translational kinetic energy of a gas molecule is 3kT/2, so at the same temperature it has the same average value for all ideal…

• A. double
• B. one half
• C. four times
• D. one fourth

Explanation: Boyle's law at constant temperature states PV = constant, so P1V1 = P2V2.

• A. 460°C
• B. 280°C
• C. 360°C
• D. 160°C

Explanation: Use F = (9/5)C + 32 and set the Fahrenheit reading equal to twice the Celsius reading: 2C = (9/5)C + 32, so (1/5)C = 32 and C = 160°C.

• A. 76cm 0°C
• B. 760mm 273K
• C. 1atm 273K
• D. all of the aboveTracking Hyperlocal Weather Forecasts

Explanation: These are equivalent descriptions of standard temperature and pressure: 76 cm Hg = 760 mm Hg = 1 atm, and 0°C = 273 K.

• A. One degree of Fahrenheit scale
• B. 1.8 degrees of Fahrenheit scale
• C. 3.2 degrees of Fahrenheit scale
• D. 2.12 degrees of Fahrenheit scale

Explanation: The interval conversion is ΔF = (9/5)ΔC. Hence, a change of 1°C corresponds to (9/5) × 1 = 1.8°F, so it is 1.8 degrees on the Fahrenheit…

• A. 37°C
• B. 42°C
• C. 55°C
• D. 410°C

Explanation: Convert using C = (5/9)(F - 32): C = (5/9)(98.6°F - 32°F) = (5/9)(66.6°F) = 37°C. Thus normal body temperature is approximately 37°C.

• A. 1.38 x 10^-31JK-1
• B. 3.18 x 10^-31JK-1
• C. 3.18 x 10^-23JK-1
• D. 1.38 x 10^-23JK-1

Explanation: Boltzmann's constant has the value k = 1.38 x 10^-23 J K^-1, linking temperature with the energy of individual particles.

• A. Over a wide range of temperature its expansion is uniform
• B. It does not stick to thermometer glass
• C. It opaque to light
• D. All of above

Explanation: Mercury is useful in thermometers because it expands nearly uniformly over a useful temperature range, does not wet or stick to glass, and…

• A. Mercury takes a long time to contract
• B. The amount of mercury use is very small
• C. The capillary tube has a small constriction near the bulb
• D. The capillary tube is very narrow

Explanation: A clinical thermometer has a narrow constriction near the bulb that prevents the mercury column from returning immediately when the…

• A. its pressure is constant
• B. its pressure rises
• C. its pressure falls
• D. any of above

Explanation: At constant volume, the ideal-gas relation P/T = constant applies, so pressure increases directly with absolute temperature.