WX201 UNIT 2 EXAM QUESTIONS AND
ANSWERS 100% PASS 2026/2027
Three phases of water - ANS Solid (lowest energy, hexagonal structure), Liquid (medium
energy, flows), Gas (highest energy, molecules far apart)
Six phase changes of water - ANS Melting, Evaporation, Sublimation (cool environment);
Freezing, Condensation, Deposition (warm environment)
Latent heat - ANS Energy required for phase change without temperature change
Phase changes that cool environment - ANS Melting, Evaporation, Sublimation
Phase changes that warm environment - ANS Freezing, Condensation, Deposition
Hydrologic cycle - ANS Movement of water between ocean, atmosphere, and land with
phase changes
Vapor pressure - ANS Partial pressure exerted by water vapor in air
Dalton's Law of Partial Pressures - ANS Each gas exerts pressure proportional to its
percentage of total air pressure
2026/2027 ALLRIGHTS RESERVED
1
, Saturation vapor pressure (SVP) - ANS Maximum vapor pressure possible at a given
temperature
SVP and temperature relationship - ANS Warmer air has higher SVP; colder air has lower SVP
Relative humidity (RH) - ANS (Vapor pressure / Saturation vapor pressure) × 100
Unsaturated air - ANS RH < 100%
Saturated air - ANS RH = 100%
Supersaturated air - ANS RH > 100%
Daily RH variation - ANS Highest pre-dawn; lowest afternoon due to temperature changes
Dew point - ANS Temperature air must cool to reach saturation
Dew point and moisture relationship - ANS Higher dew point = more water vapor; lower dew
point = less water vapor
Dew point depression - ANS Temperature minus dew point (T − Td)
Small dew point depression - ANS Moist air, high RH
Large dew point depression - ANS Dry air, low RH
Wet bulb temperature - ANS Lowest temperature air can reach through evaporation
2026/2027 ALLRIGHTS RESERVED
2
ANSWERS 100% PASS 2026/2027
Three phases of water - ANS Solid (lowest energy, hexagonal structure), Liquid (medium
energy, flows), Gas (highest energy, molecules far apart)
Six phase changes of water - ANS Melting, Evaporation, Sublimation (cool environment);
Freezing, Condensation, Deposition (warm environment)
Latent heat - ANS Energy required for phase change without temperature change
Phase changes that cool environment - ANS Melting, Evaporation, Sublimation
Phase changes that warm environment - ANS Freezing, Condensation, Deposition
Hydrologic cycle - ANS Movement of water between ocean, atmosphere, and land with
phase changes
Vapor pressure - ANS Partial pressure exerted by water vapor in air
Dalton's Law of Partial Pressures - ANS Each gas exerts pressure proportional to its
percentage of total air pressure
2026/2027 ALLRIGHTS RESERVED
1
, Saturation vapor pressure (SVP) - ANS Maximum vapor pressure possible at a given
temperature
SVP and temperature relationship - ANS Warmer air has higher SVP; colder air has lower SVP
Relative humidity (RH) - ANS (Vapor pressure / Saturation vapor pressure) × 100
Unsaturated air - ANS RH < 100%
Saturated air - ANS RH = 100%
Supersaturated air - ANS RH > 100%
Daily RH variation - ANS Highest pre-dawn; lowest afternoon due to temperature changes
Dew point - ANS Temperature air must cool to reach saturation
Dew point and moisture relationship - ANS Higher dew point = more water vapor; lower dew
point = less water vapor
Dew point depression - ANS Temperature minus dew point (T − Td)
Small dew point depression - ANS Moist air, high RH
Large dew point depression - ANS Dry air, low RH
Wet bulb temperature - ANS Lowest temperature air can reach through evaporation
2026/2027 ALLRIGHTS RESERVED
2