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.