CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Thermometers
What does a thermometer measure?
A. Heat energy directly
B. Mass
C. Temperature
D. Pressure only
Correct Answer: C
A thermometer measures temperature using a calibrated physical property.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Radiation
What kind of electromagnetic radiation is strongly associated with heat emission from objects near room temperature?
A. Gamma rays
B. X-rays
C. Ultraviolet only
D. Infrared
Correct Answer: D
Objects at ordinary temperatures emit most strongly in infrared wavelengths.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Radiation
Which law states that radiated power rises strongly with absolute temperature?
A. Snell's law
B. Boyle's law
C. Ohm's law
D. Stefan-Boltzmann law
Correct Answer: D
Blackbody radiated power is proportional to the fourth power of absolute temperature.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Radiation
Which surfaces are generally good absorbers and emitters of thermal radiation?
A. Shiny polished surfaces
B. Perfect mirrors only
C. Transparent vacuum
D. Dark, dull surfaces
Correct Answer: D
Dark matte surfaces typically have high absorptivity and emissivity.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Radiation
How does heat from the Sun reach Earth?
A. Radiation
B. Conduction through space
C. Convection through vacuum
D. Diffusion of air from the Sun
Correct Answer: A
Space is largely vacuum, so solar energy arrives as electromagnetic radiation.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Radiation
Does thermal radiation require a material medium?
A. Yes, always
B. No
C. Only solids
D. Only liquids
Correct Answer: B
Radiation can travel through vacuum.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Radiation
What is thermal radiation?
A. Heat transfer only by direct contact
B. Movement of atoms without energy
C. Heat transfer only by fluid motion
D. Transfer of energy by electromagnetic waves emitted due to temperature
Correct Answer: D
All objects above absolute zero emit electromagnetic radiation.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Heat Transfer
What is thermal equilibrium?
A. A state with infinite heat flow
B. A state where one object is always hotter
C. A state with no particles
D. A state in which bodies in contact have no net heat flow because their temperatures are equal
Correct Answer: D
Equal temperature eliminates net thermal energy transfer between bodies in contact.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Heat Transfer
What direction does heat spontaneously flow between two bodies in thermal contact?
A. In both directions equally with no net transfer always
B. Only upward
C. From lower to higher without work
D. From higher temperature to lower temperature
Correct Answer: D
Net heat transfer proceeds from hotter to cooler bodies until equilibrium.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Heat Transfer
Which mode mainly transports heat by circulating boiling water?
A. Sublimation
B. Conduction only
C. Convection
D. Radiation only
Correct Answer: C
Bulk fluid motion distributes heat through the water.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Heat Transfer
Which mode dominates heat transfer through a metal spoon in hot tea?
A. Convection within the solid
B. Conduction
C. Evaporation
D. Radiation only
Correct Answer: B
Energy moves along the solid mainly through conduction.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Heat Transfer
Which heat-transfer mode can occur through a vacuum?
A. Conduction only
B. Radiation
C. Both conduction and convection without matter
D. Convection only
Correct Answer: B
Thermal radiation travels as electromagnetic waves and needs no material medium.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Heat Transfer
What are the three main modes of heat transfer?
A. Conduction, convection and radiation
B. Reflection, refraction and diffraction
C. Evaporation, freezing and melting only
D. Voltage, current and resistance
Correct Answer: A
Thermal energy moves by conduction, convection and electromagnetic radiation.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Expansion of Matter
Water has an unusual expansion behavior near which temperature?
A. 0 K only
B. 50°C
C. 100°C only
D. 4°C
Correct Answer: D
Liquid water reaches maximum density near 4°C and expands when cooled below this point.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Expansion of Matter
Does heating generally change the mass of a solid in ordinary thermal expansion?
A. Mass changes into temperature
B. Mass becomes zero
C. No, mass remains essentially unchanged
D. Yes, mass always doubles
Correct Answer: C
Thermal expansion changes dimensions, not the amount of matter.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Expansion of Matter
Which device uses unequal thermal expansion of two metals?
A. Microscope
B. Ammeter
C. Barometer
D. Bimetallic strip thermostat
Correct Answer: D
Two bonded metals with different expansion coefficients bend as temperature changes.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Expansion of Matter
Why are expansion gaps left in bridges and railway tracks?
A. To increase electrical resistance
B. To allow thermal expansion without buckling or damage
C. To absorb sound only
D. To reduce gravity
Correct Answer: B
Structures need room to expand and contract as temperature changes.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Expansion of Matter
What is linear expansion?
A. Change in length due to temperature change
B. Change in color
C. Change in mass
D. Change in charge
Correct Answer: A
Linear expansion concerns one-dimensional length change.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Expansion of Matter
What generally happens to most materials when heated?
A. They always contract
B. Their mass doubles
C. They expand
D. They become weightless
Correct Answer: C
Higher temperature usually increases average particle spacing.
CSS - PMS - CCE - PCS - General Science
Heat & Thermodynamics - Convection
What is forced convection?
A. Radiation from the Sun
B. Convection enhanced by a fan, pump or other external mechanism
C. Conduction in copper only
D. Convection without any fluid
Correct Answer: B
Fans and pumps move fluid and increase convective heat transfer.