Population Density

Correct answer: C. 200 persons per square kilometre

Explanation: To find density, divide the total number of people by the total area. This operation tells us the average population associated with one square kilometre. The zeros in both numbers can be cancelled carefully, but the units must remain persons per square kilometre. Density is not found by adding population and area or by selecting one of the given numbers without calculation.

The required calculation is \(500000 \div 2500 = 200\). Therefore the region has a density of 200 persons per square kilometre, so option C is correct. A quick check confirms this: \(2500 \times 200 = 500000\). The values 100, 150, and 250 do not reproduce the stated population when multiplied by 2500, so they cannot be the correct density.

Correct answer: A. It shows how densely or sparsely people are settled in an area

Explanation: Population density describes how many people live in relation to the land area of a place. The basic arithmetic density is calculated as total population divided by total area, usually expressed as persons per square kilometre. This measure helps geographers compare places and identify whether settlement is relatively concentrated or sparse. It also assists planning for housing, transport, schools, health care, and other services.

Option A is correct because density directly describes the concentration of people over space. The other options concern weather, mountain height, or river length, which are different geographical subjects. Density does not by itself explain every reason for settlement, nor does it show the exact distribution inside every neighbourhood, but it provides an important broad comparison between regions. Its value lies in connecting population size with the land available.

Correct answer: C. 200 persons per square kilometre

Explanation: Population density tells us how many people live, on average, in one square kilometre. Its formula is \(Population\ Density=\frac{Total\ Population}{Total\ Area}\). Here the population is 180,000 and the area is 900 square kilometres, so the calculation is \(180000\div900=200\) persons per square kilometre.

Thus option C is correct. A quick check also helps: 900 multiplied by 200 equals 180,000, so the units and result agree. Option A would give only 90,000 people for 900 square kilometres, while 150 and 300 would produce different totals. Density is an average for the whole region; it does not mean that every square kilometre has exactly the same number of residents.

Correct answer: C. 50000 people

Explanation: Population density tells us how many people live in one unit of area. The relationship is \(\text{Population Density}=\frac{\text{Total Population}}{\text{Total Area}}\). To find total population, multiply density by area: \(\text{Total Population}=125\times400=50,000\). The units also confirm the calculation because persons per square kilometre multiplied by square kilometres leaves persons.

Therefore the region contains 50,000 people, so option C is correct. Option A is half of the calculated value, option B incorrectly uses only the area-related figure, and option D is larger than the correct product. The answer follows directly from the definition of density and does not require any additional geographical assumption.

Correct answer: A. Number of people living per unit area

Explanation: Population density means the number of people living in a given unit of area. It helps us compare how closely people are distributed in different places, even when those places have different total sizes. The correct answer is A. In its basic form, arithmetic density is calculated as total population divided by total land area, and it is often expressed as people per square kilometre.

The other options describe different things: birth rate measures births, rainfall measures precipitation, and the population of cities is only one part of a region’s population. Density does not require a place to be urban; a village, district, or country can also have a population density. Therefore, the idea is about people in relation to area, not about births, rain, or cities alone.

Correct answer: B. \(Population\ Density = \frac{Population}{Area}\)

Explanation: Population density tells us how many people live, on average, in one unit of area. It helps compare how crowded different regions are. The unit is commonly persons per square kilometre, although another area unit may be used when appropriate. Density is an average, so it does not mean that people are spread equally everywhere.

The formula is \(\text{Population Density}=\frac{\text{Population}}{\text{Area}}\). Thus, the total number of people is divided by the total land area. Option B is correct. Option A reverses the quantities and gives area per person, while multiplication and addition do not produce a density measurement.

Correct answer: C. Persons per square kilometre

Explanation: Population density measures how many people live in a given unit of land area. A common unit is persons per square kilometre, written as persons/km². It relates a population total to the area occupied by that population. For example, if 10,000 people live in 20 square kilometres, density is 500 persons per square kilometre.

Option C gives exactly this standard unit. Kilometres per person reverses the relationship, while people per year measures a time-based quantity such as population change. Percent per square kilometre is not the normal unit for ordinary population density. Therefore, the third choice follows from the meaning and measurement of density.

Correct answer: D. It will generally decrease

Explanation: Population density is calculated by dividing total population by total area: \(D=\frac{P}{A}\). If the population remains constant while the area becomes larger, the same number of people is spread across more land. The denominator increases, so the value of the fraction becomes smaller. Therefore, density will generally decrease, as stated in option D.

For example, 1,000 people living in 10 square kilometres give a density of 100 people per square kilometre. If the area becomes 20 square kilometres while the population remains 1,000, density becomes 50. It does not double, remain unchanged, or become zero. The exact fall depends on how much the area increases.

Correct answer: A. Population density will increase

Explanation: Answer: A, population density will increase. Density is calculated as population divided by area. When the area stays fixed, it remains the denominator. If the number of people increases, the numerator becomes larger, so the quotient also becomes larger. For example, 1,000 people in 10 square kilometres give a density of 100 persons per square kilometre; 1,500 people in the same 10 square kilometres give 150 persons per square kilometre. B gives the opposite result. C is impossible under the stated condition because adding people cannot make the ratio automatically zero. D is wrong because area does not expand merely because population increases; physical area and population are separate quantities. Memory cue: more people in the same space means greater crowding on average and higher density.

Correct answer: B. The one with the larger population

Explanation: Answer: B, the region with the larger population. Population density tells us how many people live, on average, in one unit of area. The formula is population density = total population ÷ total area. Here the areas are equal, so the denominator in both comparisons is the same. If one region has more people, dividing the larger population by the same area gives a larger density. For example, 10,000 people in 100 square kilometres give 100 people per square kilometre, while 20,000 people in the same area give 200. A is wrong because fewer people in the same area produce lower density. C is wrong because equal area does not mean equal population. D is wrong because rainfall may influence settlement, but it is not part of the density calculation. Memory cue: with equal area, more people means more density.

Correct answer: C. The one with the smaller area

Explanation: Population density measures how many people occupy a given unit of land. It is calculated as population divided by area, commonly written as density = population / area. If two regions contain the same number of people, the region with less land has those people concentrated in a smaller space. Its numerical density must therefore be higher. The larger region spreads the same population over more land and has a lower value.

Option C is correct because area is the denominator in the density calculation. For example, 10,000 people in 100 square kilometres gives 100 persons per square kilometre, while the same 10,000 people in 200 square kilometres gives 50 persons per square kilometre. Option A reverses the relationship. Equal population does not mean equal density unless the areas are also equal, so B is wrong. Rainfall alone does not determine this comparison, making D irrelevant.

Correct answer: D. Small population and very large area

Explanation: Population density is the number of people divided by the area they occupy. A density is lowest when there are comparatively few people and a very large area. In that situation, the same population is spread widely, so each square kilometre contains only a small number of people. Therefore, the correct choice is D: small population and very large area.

The other choices combine a large or medium population with a small or medium area. Those combinations produce a higher ratio because many people are concentrated in less space. A very large population in a small area would give especially high density, not low density. This question concerns the ratio of population to area, not population size alone or the total size of the region alone.

Correct answer: A. Very large population and small area

Explanation: Population density is calculated by dividing total population by total area: \(\text{density}=\frac{\text{population}}{\text{area}}\). The value becomes large when the numerator, population, is large and the denominator, area, is small. This does not mean that every part of the area has exactly the same number of people; it is an average for the whole stated area. The comparison must therefore consider both population size and land area.

Option A is correct because a very large population concentrated within a small area produces the largest ratio among the listed situations. A small population over a large area gives a low ratio, as in option B. A small population and small area could produce different results depending on the exact figures, while a very large area tends to reduce density, as in option D. The formula directly supports the answer.

Correct answer: B. How closely people are concentrated within an area

Explanation: Population density is a measure of how many people live in a given unit of land, usually one square kilometre. It helps us understand whether people are spread thinly or concentrated closely in an area. Density is an average for the whole area, so it may hide differences between crowded towns and sparsely settled countryside, but it still provides a useful general picture of settlement concentration.

Option B is correct because it directly describes the main meaning of population density. Options A and C refer to rainfall and birth rate, which are different geographical or demographic measures. Option D is also incorrect because density includes the population living in both urban and rural places, unless a question specifically asks for urban density. Therefore, knowing density mainly tells us how closely people are settled within an area. The supplied answer is accurate.

Correct answer: C. 100 persons per square kilometre

Explanation: Population density is found by dividing the total population by the total area. The unit must be kept clear: people per square kilometre. Here the population is 100,000 and the area is 1,000 square kilometres. Thus, \(100000 \div 1000 = 100\). This means that the region has an average of 100 people for each square kilometre.

Therefore, option C is correct. Option A would result from dividing by 10,000, option B does not follow from the given figures, and option D would result from reversing the relationship incorrectly. Density is a ratio, so a larger population raises it, while a larger area lowers it when population remains unchanged. The calculation supports 100 persons per square kilometre.

Correct answer: D. 100 persons per square kilometre

Explanation: Population density tells us how many people live in one unit of area. The required operation is division: \(\text{Density}=\frac{\text{Population}}{\text{Area}}\). Substituting the given values gives \(\frac{50000}{500}=100\). The unit is persons per square kilometre because the population is divided by an area measured in square kilometres.

Thus, the correct choice is option D, 100 persons per square kilometre. The other values result from using an incorrect division or from not completing the calculation. It is important to keep the units with the answer and to check that multiplying 100 persons per square kilometre by 500 square kilometres returns the original population of 50,000.

Correct answer: A. 40 persons per square kilometre

Explanation: Population density tells us how many people live, on average, in one unit of area. The required calculation is \(\text{Density}=\frac{\text{Population}}{\text{Area}}\). Substituting the given values gives \(\frac{24000}{600}=40\). The unit is persons per square kilometre because the area is measured in square kilometres.

Therefore, option A, 40 persons per square kilometre, is correct. A common mistake is to multiply population and area or to divide in the reverse order. Density must always be found by dividing the number of people by the amount of land. The result also means that, on average, every square kilometre contains 40 people, not that every location has exactly 40 residents.

Correct answer: B. The 100 square kilometre area

Explanation: Population density means the number of people living in one unit of area. When the populations are equal, the area becomes the deciding factor: the smaller area has more people packed into each square kilometre. This is why density is not simply a count of population; it relates population to land area.

For the first area, density is \(20000/100=200\) people per square kilometre. For the second, it is \(20000/200=100\) people per square kilometre. Since 200 is greater than 100, the 100-square-kilometre area has the higher density. Therefore, option B is correct. Option A would be correct only if the areas were also equal.

Correct answer: C. The area with population 60000

Explanation: Population density is calculated by dividing population by area: \(Density=\frac{Population}{Area}\). Here both areas are equal, 300 square kilometres, so the region with more people must have more people in each square kilometre. For the first region, \(30000\div300=100\) persons per square kilometre. For the second, \(60000\div300=200\) persons per square kilometre.

Therefore, the area containing 60,000 people has the higher density, so option C is correct. Equal area does not make the densities equal; equal density would require equal populations as well. Option A reverses the comparison, while option D is incorrect because density can be calculated easily when both population and area are provided.

Correct answer: D. Many people live within a limited area

Explanation: Population density means the number of people living in a given unit of area, commonly one square kilometre. High density therefore means that many people are concentrated in a relatively small or limited area. It is a measure of concentration, not simply the total population of a place.

Option D expresses this meaning directly: many people live within a limited area. Option A describes low density because few people are spread across a large area. Option C is incorrect because rural areas also contain population, and option B is wrong because area is part of the density calculation. Thus D is the best choice.

Correct answer: A. Few people are spread over a large area

Explanation: Answer: A, few people spread over a large area. Density is the number of people per unit of area, so a low value means that the population is sparse in relation to the land available. For example, 5,000 people living in 500 square kilometres produce a density of 10 persons per square kilometre. B describes the opposite situation: many people in little space produce high density. C is not a definition of low density; it merely claims that all places have the same value. D is insufficient because the number of cities alone does not tell us the total population or the area. A region can have few cities but still have high density in its settled parts. The useful cue is: low density means fewer people per unit area, or sparse settlement.

Correct answer: B. Density gives people per area while distribution shows where people live

Explanation: Density and distribution describe related but different aspects of population. Density is a numerical measure: it tells us the number of people living in each unit of area. Distribution is a spatial description: it shows where people are located, whether they are spread evenly, concentrated in cities, clustered near coasts, or sparse in difficult environments. A map may show distribution, while a calculation gives density.

Therefore, option B is correct. It clearly states that density gives people per area and distribution shows where people live. Option A wrongly treats the concepts as identical. Options C and D confuse population distribution or density with birth rate and migration; those are factors or demographic processes, not the meanings of these two terms.

Correct answer: C. Density will increase

Explanation: Population density is found by dividing population by area: \(D=\frac{P}{A}\). In this situation, the area of the city stays fixed, so the denominator does not change. The number of residents increases, so the numerator becomes larger. Dividing a larger population by the same area necessarily gives a larger density. More people are therefore occupying the same amount of space.

The correct choice is option C, density will increase. Option A would apply if the population fell or the area expanded while population stayed fixed. Option B is impossible unless the population were zero. Option D is wrong because density can change whenever population changes, even when the area remains constant. The statement concerns total residents, not the physical size of the city.

Correct answer: D. Density will also become half

Explanation: When area remains constant, population density changes in the same proportion as population. The formula is density = population divided by area. If the population becomes one-half of its original value and the denominator does not change, the quotient also becomes one-half. Thus the correct choice is D: density will also become half.

Suppose a region has 10,000 people in 100 square kilometres. Its density is 100 people per square kilometre. If the population falls to 5,000 while the area remains 100 square kilometres, the new density is 50 people per square kilometre. It does not double, remain unchanged, or become four times as large, because none of those results follows from reducing only the population by half.

Correct answer: A. 200 persons per square kilometre

Explanation: Population density tells us how many people live, on average, in one unit of area. It is found by dividing the total population by the total area. The unit here is persons per square kilometre, so both the population and area must be used in the calculation.

Using the formula \(\text{Density}=\frac{\text{Population}}{\text{Area}}\), we get \(\frac{80000}{400}=200\). Thus, every square kilometre contains an average of 200 people. Therefore, option A, 200 persons per square kilometre, is correct. The other options result from using an incorrect division or from confusing population with density.