Question 1

The terminal velocity of an object depends primarily upon:
A)its composition.
B)its shape.
C)its size.
D)the temperature.

Accepted Answer

C

Question 2

The collision efficiency:
A)is approximately one regardless of drop size.
B)is affected by the compression of air just below the collector drop.
C)is governed primarily by the temperature of the air.
D)is highest for droplets of equal or nearly equal size.

Accepted Answer

The collision efficiency is affected by the compression of air just below the collector drop. This is because the compressed air increases the likelihood of collisions between drops, leading to more efficient coalescence. The other options are incorrect because A is not true as larger drops are more efficient in collision, C is not true as temperature primarily affects the stability of clouds and fog, and D is not true as larger drops have a higher collision efficiency.

Question 3

During coalescence,the percentage of colliding droplets that join together is called the:
A)droplet collection coefficient.
B)coalescence efficiency.
C)rain potential efficiency.
D)coalescence condensation collection factor.
E)none of the above

Accepted Answer

Coalescence efficiency refers to the percentage of colliding droplets that successfully merge into a single larger droplet during the coalescence process.

Question 4

Ice crystal growth rates are enhanced by which of the following?
A)deposition of water vapor to ice alone
B)riming
C)aggregation
D)all of the above

Accepted Answer

All three processes, deposition of water vapor to ice alone, riming and aggregation, enhance ice crystal growth rates. Deposition involves the direct conversion of water vapor to ice without going through the liquid phase. Riming involves the growth of ice crystals due to the impact of supercooled liquid droplets, while aggregation involves the sticking together of ice crystals to form larger ones.

Question 5

The process by which supercooled water droplets freeze onto falling ice crystals is called:
A)riming.
B)aggregation.
C)cold-cloud condensation.
D)Bergeron bonding.

Accepted Answer

Riming occurs when supercooled water droplets freeze onto falling ice crystals, often leading to the formation of graupel or rime ice.

Question 6

Drag between the droplet and surrounding air depends on:
A)the rate of fall.
B)the size of the droplet.
C)both A and B
D)none of the above

Accepted Answer

The drag force experienced by a falling droplet is dependent on both the rate of fall and the size of the droplet, as these factors affect the balance between gravitational force and air resistance. Therefore, both options A and B are correct.

Question 7

Cool clouds:
A)contain no water droplets above 0 degrees Celsius.
B)contain substantial numbers of ice crystals at all elevations within the clouds.
C)have regions with above-freezing temperatures.
D)typically form precipitation through the collision-coalescence process.

Accepted Answer

Cool clouds can have regions where temperatures are above freezing, allowing for the presence of liquid water droplets.

Question 8

The smallest terminal velocities are for:
A)condensation nuclei.
B)cloud droplets.
C)raindrops.
D)none of the above

Accepted Answer

Condensation nuclei are smaller than cloud droplets and raindrops, leading to smaller terminal velocities due to less air resistance.

Question 9

Terminal velocity is achieved when:
A)you enter the freeway from the on-ramp.
B)Nolan Ryan's fastball impacts the catcher's mitt.
C)gravity is equalized by spinning.
D)there is a balance between the falling body and the drag of atmospheric molecules.

Accepted Answer

Terminal velocity is the maximum velocity that a falling object reaches when the force of air resistance is equal to the force of gravity. At this point, the object stops accelerating and moves at a constant speed. Therefore, choice D is the correct answer as it describes the balance between the falling body and the drag of atmospheric molecules that characterizes terminal velocity.

Question 10

Collision-coalescence is the predominant cause of precipitation in this region:
A)above the Arctic Circle.
B)subpolar latitudes.
C)mid-latitudes.
D)the Tropics.

Accepted Answer

Collision-coalescence is the predominant cause of precipitation in the Tropics, where warm and moist air rises and cools, causing water vapor to condense and form precipitation.

Question 11

In the Bergeron-Findeisen process,the cloud is:
A)raining.
B)snowing.
C)sleeting.
D)entirely above freezing.
E)Part of the cloud is above freezing, and part of the cloud is below freezing.

Accepted Answer

The Bergeron-Findeisen process occurs in mixed-phase clouds, where part of the cloud is below freezing and part of the cloud is above freezing. In this process, the ice crystals in the upper portion of the cloud grow at the expense of the liquid droplets in the lower portion, leading to precipitation in the form of either rain or snow depending on the temperature and other conditions. Thus, option E is the best choice.

Question 12

In the collision-coalescence process,the entire cloud is:
A)raining.
B)snowing.
C)below freezing.
D)above freezing.

Accepted Answer

The collision-coalescence process occurs in warm clouds, which means that the temperature is above 0°C (32°F). Therefore, the best choice is D, above freezing. The cloud may or may not be raining or snowing at the time, as those processes occur in different conditions within the cloud.

Question 13

Formation of ice crystals can occur with saturation at temperatures between:
A)0 and 5 degrees C.
B)0 and -5 degrees C.
C)-4 and -40 degrees C.
D)-40 and -60 degrees C.

Accepted Answer

Ice crystals can form in the atmosphere when the temperature is between -4 and -40 degrees Celsius, given that the air is saturated. This temperature range is conducive to the formation of ice nuclei, around which ice crystals can grow.

Question 14

A collector drop will have the highest collision efficiency with this size drop:
A)drops that are much larger.
B)drops that are about the same size.
C)drops that are somewhat smaller.
D)drops that are very much smaller.

Accepted Answer

The answer of A collector drop will have the highest...

Question 15

Cloud droplets fall slowly because they:
A)are small.
B)carry an electric charge.
C)easily get caught in downdrafts.
D)have not adhered to condensation nuclei.

Accepted Answer

Cloud droplets are very small and range from 0.01 to 0.02 mm in diameter. Due to their small size, they have a low mass and experience very little air resistance, which causes them to fall slowly.

Question 16

The collision-coalescence process:
A)is most common at high latitudes.
B)is most frequent in cold clouds.
C)is dependent upon the different downward velocities of different-sized droplets.
D)explains the formation of snow better than it explains the formation of rain.

Accepted Answer

The collision-coalescence process involves the collision of smaller cloud droplets with larger droplets, leading to the coalescence and formation of larger droplets. This process is dependent upon the different downward velocities of different-sized droplets, as larger droplets fall faster and are more likely to collide with smaller droplets. This process is more common in warm clouds and is an important process in the formation of rain.

Question 17

Cloud droplet growth by condensation is very rapid for:
A)large cloud droplets.
B)supercooled water droplets.
C)ice crystals.
D)small cloud droplets.
E)none of the above

Accepted Answer

Small cloud droplets have a high surface area-to-volume ratio which allows for rapid condensation and subsequent growth. As the droplet grows, the rate of condensation slows down due to a decrease in the surface area-to-volume ratio. Large droplets, ice crystals, and supercooled water droplets also experience growth by condensation, but not as rapidly as small cloud droplets.

Question 18

Raindrops fall because:
A)they are large compared to atmospheric molecules.
B)they are small compared to atmospheric molecules.
C)they become large enough that gravity can pull them out of the sky.
D)they roll down isentropic surfaces and can't be stopped.

Accepted Answer

Raindrops form when water vapor in the atmosphere condenses onto tiny particles called cloud condensation nuclei. As more water vapor condenses onto these particles, the droplets grow in size until they become heavy enough to fall due to gravity. This means that raindrops fall because they become large enough that gravity can pull them out of the sky.

Question 19

The acceleration of gravity is opposed by the atmosphere in the form of:
A)drag.
B)viscosity.
C)thermal inversions.
D)winds.

Accepted Answer

The atmosphere opposes the acceleration of gravity through the force of drag, which is caused by air resistance. This resistance increases as an object moves faster through the air and is in the opposite direction of the object's motion.

Question 20

The Bergeron process:
A)is most common in the Tropics.
B)is dependent on the growth of ice crystals.
C)can take place in cool clouds, but not cold clouds.
D)is not dependent on changes in vapor pressure.

Accepted Answer

The Bergeron process is a mechanism of precipitation formation that involves the growth of ice crystals by vapor deposition in cold clouds. Therefore, it is dependent on the growth of ice crystals.

Quiz 7: Precipitation Processes

The terminal velocity of an object depends primarily upon:

The collision efficiency:

During coalescence,the percentage of colliding droplets that join together is called the:

Ice crystal growth rates are enhanced by which of the following?

The process by which supercooled water droplets freeze onto falling ice crystals is called:

Drag between the droplet and surrounding air depends on:

Cool clouds:

The smallest terminal velocities are for:

Terminal velocity is achieved when:

Collision-coalescence is the predominant cause of precipitation in this region:

In the Bergeron-Findeisen process,the cloud is:

In the collision-coalescence process,the entire cloud is:

Formation of ice crystals can occur with saturation at temperatures between:

A collector drop will have the highest collision efficiency with this size drop:

Cloud droplets fall slowly because they:

The collision-coalescence process:

Cloud droplet growth by condensation is very rapid for:

Raindrops fall because:

The acceleration of gravity is opposed by the atmosphere in the form of:

The Bergeron process: