Population Density

A cyclone is a low-pressure system in which air converges toward the centre. In the Southern Hemisphere, the Coriolis effect deflects moving air to the left, producing an overall clockwise circulation around the low-pressure centre. This is opposite to the usual anticlockwise circulation of a cyclone in the Northern Hemisphere. The exact wind pattern may be affected by friction and local conditions, but clockwise is the standard answer.

Population density is a ratio showing the number of people relative to a unit of land area, but it does not describe the quality of life of those people. Two regions may have the same density while differing greatly in average income, employment, housing, sanitation, healthcare, education, transport, natural resources, public services and governance. The distribution of people within each region may also differ, as can inequality and access to facilities. Thus option A is correct. Density remains useful for comparing population pressure, but it is not a complete welfare indicator. The other options are incorrect because density is not always wrong, population conditions do matter, and climate is only one of many influences.

Correct answer: B. Population distribution is usually the result of several interacting factors rather than one condition alone. Cyclones create danger, possible damage, and higher settlement costs, so they may discourage or limit settlement in some places. However, a major port and industries provide jobs, trade, transport connections, and services. These economic advantages can attract workers and businesses, even though people still face environmental risk. Therefore, the final population pattern reflects both the physical hazard and the economic attraction. A is too absolute: cyclone risk does not mean that every person avoids the coast. C is false because a port does not remove or stop cyclones. D is incomplete because coastline length alone cannot explain population. Memory cue: in geography, weigh opposing push and pull factors together.

Correct answer: D. Housing cost is an economic factor that influences where households can afford to live. If homes in the city centre become too expensive, some families may search for less costly housing in suburbs or peripheral areas. If transport links are available, they may continue travelling to central jobs and services. Step by step, higher prices reduce affordability, reduced affordability encourages residential movement, and that movement changes the distribution of people within the urban region. A is wrong because not every household can or will remain in the centre. B ignores the clear effect of affordability on choice. C concerns weather and is unrelated to the stated economic process. The word “possible” is important: outward movement may occur, but it is not inevitable for every household. Memory cue: expensive centres often push some residents toward cheaper edges.

Correct answer: C. Tourism is an economic activity that can create employment in hotels, restaurants, transport, guiding, recreation, construction, and other services. As these activities expand, workers may move to the island or local residents may remain because more jobs are available. New services and infrastructure can also support settlement growth. Therefore, the island’s population may increase or become more concentrated in tourist locations. A is the opposite of the likely attraction and is too absolute. B describes an environmental possibility but does not explain the direct population effect asked about. D is wrong because employment is a major reason why economic activities attract people. The result is not guaranteed; island resources, housing, transport, and carrying capacity may limit growth. Memory cue: new jobs can pull people toward a place.

Correct answer: C. A railway can reduce travel time and transport costs, allowing farmers to sell produce in larger or more distant markets. Better market access may improve farm income and make agricultural activity more profitable. Higher income can support local shops, storage, processing, transport services, and other employment. These changes may retain residents, attract workers, and encourage the growth of settlements near railway stations or productive farming areas. A is incorrect because improved transport generally supports market access rather than automatically ending agriculture. B is incorrect because a railway changes connectivity, not the regional climate. D is too absolute because transport improvements can influence economic opportunity and settlement patterns, even though the exact result depends on other conditions. Memory cue: transport changes access; access can change income, jobs, and settlement.

Correct answer: D. A favorable climate can support living and economic activities, but safe drinking water is a basic requirement for healthy settlement. Contaminated water can increase health risks, raise the burden on households and public services, and make the area less attractive to residents and potential migrants. Some people may therefore avoid the region or move toward places with safer water. A is incorrect because one favorable condition cannot remove every other problem. B is unsupported because population does not automatically double when climate is pleasant. C is too narrow: contaminated water can affect health, domestic life, and settlement decisions, not only agriculture. The question illustrates that population distribution results from the combined effect of several factors. Memory cue: a favorable factor may be outweighed by a serious basic-need problem.

Correct answer: A. When climate is similar, differences in human conditions become more important in explaining population attraction. Good schools, hospitals, sanitation, and other services improve quality of life and may attract families, students, workers, and professionals. The area with better services may therefore gain population, although the outcome is not mechanically guaranteed because jobs, housing, and transport also matter. B is contrary to the usual attraction of better facilities. C is wrong because equal climate does not make all social conditions equal. D is absurd because both areas can have population. Memory cue: people choose not only a physical environment but also a quality of life.

Correct answer: D. Housing cost is an important factor in residential location. If central accommodation becomes unaffordable, some households may look for less expensive homes in the suburbs. Good transport connectivity makes suburban living practical because residents can commute to central jobs, schools, and services. Consequently, suburban residential population may increase and the central share may change. A is wrong because high prices do not guarantee rising central density. B is the opposite of the likely effect. C is unrelated: housing prices do not automatically eliminate jobs. Memory cue: affordability plus accessibility encourages suburbanization.

Correct answer: C. Climate and water are important physical conditions for settlement, but people also consider the quality of life offered by a place. Health care is especially important for children, older people, pregnant women, and families needing regular treatment. If medical facilities are poor, some people may avoid moving there, while existing residents may leave when better services are available elsewhere. Option A is wrong because pleasant climate does not remove the need for doctors, hospitals, or medicines. Option B is wrong because water is important but is not the only population factor. Option C is correct because poor services reduce the attractiveness of long-term residence. Option D is wrong because services strongly influence settlement decisions. Memory cue: favourable nature attracts, but adequate services help people stay.

Correct answer: D. A mountain town may depend on roads for visitors, supplies, education, health care, and employment. Tourism supports hotels, restaurants, shops, guiding, transport, and related activities. If access remains blocked, visitors may decline and tourism-based jobs may become less available. Residents, especially workers who cannot find other employment, may move to towns with better opportunities. This is called out-migration and can reduce or redistribute the town’s population. Option A is wrong because loss of jobs does not necessarily increase population. Option B is wrong because road blockage does not immediately change climate. Option C is wrong because tourism is an economic factor that can influence settlement. Option D is correct because reduced accessibility and employment may encourage people to leave. Memory cue: blocked access can weaken economic functions and push people outward.

Correct answer: B. Border towns often depend on the movement of people, goods, vehicles, and services across or near the boundary. Strict restrictions may reduce trade, transport, tourism, markets, and related employment. If economic opportunities become weaker, the town may attract fewer new residents and some existing workers may move elsewhere. Therefore, population growth or concentration can slow down, although the exact outcome depends on the local economy and the duration of restrictions. Option A is wrong because stricter controls do not automatically increase trade. Option B is correct because reduced cross-border activity can weaken employment and settlement attraction. Option C is wrong because political and economic conditions also matter. Option D is wrong because restrictions do not always increase settlement. Memory cue: a border town’s population often reflects the openness of its economic connections.

Correct answer: D. Mining can attract workers because it provides employment and income. However, severe pollution and rising health risks can reduce the quality and safety of life in the region. Households may compare the benefit of employment with the costs of illness, unsafe surroundings and poor living conditions. Some families may therefore move away even though jobs remain available. D is correct because it recognises that economic attraction and environmental disadvantages can operate at the same time. A is wrong because population growth is not guaranteed. B is wrong because jobs cannot automatically remove pollution or health risks. C is wrong because ore quality is only one economic factor and does not cancel environmental effects. Memory cue: a place can attract workers economically while pushing some residents away environmentally.

Population density tells us how many people live, on average, in one unit of land. The standard calculation is \(Population\ density = \frac{Population}{Area}\). Here the population is 180,000 and the area is 900 square kilometres. Dividing gives \(180000 \div 900 = 200\). The unit remains persons per square kilometre because people are being divided by square kilometres.

Therefore, the density is 200 persons per square kilometre, so option C is correct. A quick check also helps: 900 multiplied by 200 equals 180,000. Option A would give only 90,000 people in 900 square kilometres, while the larger values in B and D would imply populations greater than the stated total. The calculation and unit both support C.

Population density tells us how many people live in one unit of area. Therefore, when population and density are known, area is found by dividing population by density. The relationship is (\(Area = \frac{Population}{Density}\)\u0000). This prevents a common mistake: multiplying the two values instead of using the correct rearrangement.

Here, (\(Area = \frac{96000}{120} = 800\)\u0000) square kilometres. The answer is therefore option B. A quick check confirms it: 800 square kilometres with 120 people per square kilometre gives (\(800 \times 120 = 96000\)\u0000) people. The other choices do not satisfy the given population-density relationship.

Population density tells us how many people live in one unit of area. To find total population, multiply density by area: \(P = D \times A\). Here, \(P = 160 \times 450 = 72{,}000\) people. The units also confirm the calculation: persons per square kilometre multiplied by square kilometres leaves persons.

Thus, option C, 72000, is correct. Dividing instead of multiplying would give an incorrect result, and the other numbers do not follow from the given density and area. No conversion is needed because both measurements already use square kilometres.

Population density is calculated as population divided by area: \(D=P/A\). Here the populations of A and B are equal, so the only difference is the denominator. Region A has twice the area of B, meaning the same number of people is spread across twice as much land. Its density is therefore half the density of B. Equivalently, if B has density \(D\), A has \(D/2\).

Option B is correct: region B has twice the density of A. A is not twice as dense, because its larger area spreads the equal population more widely. The two densities cannot be equal unless their areas are equal, and the comparison is possible even without knowing the actual population. Thus the inverse relationship between area and density directly determines the answer.

Density is calculated by dividing population by area: \(D=\frac{P}{A}\). When two regions have exactly the same area, the denominator in this comparison is the same. Their densities therefore change in the same proportion as their populations. If region Y has population \(P\), region X has \(1.25P\), so their densities are \(P/A\) and \(1.25P/A\).

Thus X has a density 1.25 times Y's density, which means it is 25 percent higher. Option A is correct. Equal area does not mean equal density; equal density would require equal population as well. Option D is wrong because a 25 percent population difference does not become a 100 percent difference when the areas are identical.

Density is a ratio of population to area: \(D=\frac{P}{A}\). Suppose the original population is \(P\) and the original area is \(A\). After both rise by 20 percent, the new values are \(1.2P\) and \(1.2A\). Therefore, the new density is \(\frac{1.2P}{1.2A}=\frac{P}{A}\). The same multiplier appears in both numerator and denominator, so it cancels completely.

Option C is correct: density remains the same. For a simple example, 100 people in 10 square kilometres gives 10 people per square kilometre; after a 20 percent rise, 120 people in 12 square kilometres still gives 10. Option A would apply if area did not rise, and option B would require area to grow faster than population. A 40 percent increase, option D, incorrectly adds the two percentage changes instead of comparing their ratio.

Density is the ratio of population to area. When both population and area change, the new density depends on how fast each changes. Here the population becomes 150 percent of its original value, while the area becomes 125 percent of its original value. Since the population grows proportionally more than the area, more people are being placed in each unit of land.

Let the original density be \(P/A\). The new value is \(\frac{1.5P}{1.25A}=1.2\frac{P}{A}\). Thus the density becomes 1.2 times the original, or increases by 20 percent. Therefore option C, density will increase, is correct. It does not remain unchanged because population and area do not rise by the same percentage; it certainly does not become zero.

Answer: A, density will decrease by 20 percent. Population density is calculated as Population ÷ Area. When the area remains constant, any percentage change in population produces the same percentage change in density. If the original population is P and area is A, the original density is P/A. After a 20% decrease, the population becomes 0.80P, so the new density is 0.80P/A, which is 20% lower than the original density. B has the direction reversed. C incorrectly doubles the percentage decrease. D ignores the change in population. Key idea: with fixed area, density changes in the same proportion as population.

Density equals population divided by area. Let the original values be population \(P\) and area \(A\). A 25 percent fall in area leaves 75 percent of the original area, so the new area is \(0.75A\). Since population is unchanged, the new density is \(\frac{P}{0.75A}=\frac{1}{0.75}\frac{P}{A}=1.333...D\).

The new density is therefore about 133.3 percent of the old density, which means it has increased by about 33.3 percent. Option B is correct. It is not a 25 percent increase, because the denominator has become smaller and the percentage change in a ratio must be calculated from the new area carefully. A fixed population is concentrated into less space.

Density tells us how many people occupy each square kilometre. When density and area are known, total population is found by multiplying them: \(Population=Density\times Area\). In this problem, the calculation is \(320\times250\). Since \(320\times25=8000\), multiplying by ten gives \(320\times250=80000\) persons.

Thus the district has a population of 80,000, so option C is correct. The units also confirm the result: persons per square kilometre multiplied by square kilometres leaves persons. Division would be appropriate for finding density or area, not population in this case. The other choices do not result from the stated multiplication and therefore do not match the given density and area.

Population density is the number of people living in each unit of area. If population and density are known, the area can be found by reversing the density formula. This relationship is useful because population equals density multiplied by area, so area equals population divided by density. The units also confirm that people cancel, leaving square kilometres.

Here, area = population ÷ density = 135000 ÷ 90 = 1500 square kilometres. A quick check gives 90 × 1500 = 135000, so the result is consistent with the given population and density. Therefore, option C is correct. The other values would produce populations different from 135000 at a density of 90 persons per square kilometre.

Population density means the number of people living in one unit of area. It is calculated by dividing total population by total area. A region with a smaller population can still be denser if its area is much smaller.

For Region P, density is \(400000\div2000=200\) persons per square kilometre. For Region Q, it is \(300000\div1000=300\) persons per square kilometre. Since 300 is greater than 200, Region Q has the higher density. Therefore, option B is correct. The comparison must use population per unit area, not total population alone.