DGCA Meteorology: Precipitation Questions

Correct answer: A. cold clouds only

Hail requires supercooled water freezing onto growing ice stones above the freezing level, so it originates only in cold clouds; warm clouds, entirely below the 0 degree C level, cannot generate hail.

Correct answer: B. Leeward side of mountains

The leeward side gets dry air after mountains block rain on the windward side.

Correct answer: B. Clouds with large vertical development (e.g., Cumulonimbus)

Big cumulonimbus clouds have strong updrafts that form hail.

Correct answer: C. Afternoon

Over tropical land areas rainfall peaks in the afternoon, when maximum surface heating drives the deepest convection and thunderstorm development.

Correct answer: A. Afternoon

Tropical rainfall over land is greatest in the afternoon, when peak surface heating produces the strongest convection and shower or thunderstorm activity.

Correct answer: C. Ns

Nimbostratus, a thick, deep precipitating layer cloud, gives the most intensive and prolonged rain of the three; stratus yields only drizzle and cirrus precipitation never reaches the ground.

Correct answer: B. Saturation vapour pressure over the ice crystals is less than over water drops

At the same sub-zero temperature the saturation vapour pressure over ice is lower than over supercooled water, so vapour deposits onto the crystals while the drops evaporate, and the ice crystals grow at the expense of the water drops (the Bergeron process).

Correct answer: B. Cold clouds

Clouds whose tops extend well above the freezing level, and which therefore contain ice crystals and supercooled droplets, are called cold clouds.

Correct answer: A. Warm clouds

Clouds lying entirely below the freezing level, containing only liquid water warmer than 0 degrees C, are called warm clouds.

Correct answer: A. Warm clouds

The coalescence theory explains rainfall from warm clouds: droplets of different sizes, falling at different speeds, collide and merge until heavy enough to fall as rain, with no ice phase involved.

Correct answer: B. Cold clouds

The ice-crystal (Bergeron) theory explains precipitation from cold clouds, where ice crystals coexisting with supercooled droplets grow rapidly at the droplets' expense until they fall.

Correct answer: A. Maritime areas

The giant nucleus theory attributes rainfall over maritime areas to giant salt nuclei thrown up by sea spray, on which unusually large droplets form and grow quickly by coalescence.