Population Growth

Correct answer: B. 10 million

The correct answer is B. Absolute population growth is the actual numerical increase between the final and initial populations. Here the calculation is \(50\text{ million}-40\text{ million}=10\text{ million}\). Ten million is equal to 1 crore in the Indian numbering system, so the country experienced an absolute increase of 1 crore over the twenty-year period.

This measure describes the number of additional people, not the final population and not the percentage or rate of growth. Option D gives the final population, 5 crore, while C gives the initial population, 4 crore. Option A, 50 lakh, is only 5 million and is half of the actual increase. Therefore option B correctly expresses absolute population growth. The time period matters for calculating a rate, but not for finding this simple absolute difference.

Correct answer: A. The first country

Percentage growth compares an absolute increase with the population at the beginning of the period. The general calculation is \(\frac{Increase}{Initial\, population}\times100\). Both countries add 1 million people, so the numerator is identical. The difference comes from the denominator.

For the first country, 1 million is divided by a much smaller initial population. It therefore represents a larger fraction of that population. In the second country, the same million is a smaller fraction because its starting population is much larger. Thus option A is correct. Land area is relevant to density, but it is not needed to compare percentage population growth in this question.

Correct answer: C. Increase of 550

Total population change has two parts: natural change and net migration. Natural change equals births minus deaths, so it is \(1200-900=300\). Net migration equals in-migrants minus out-migrants, so it is \(500-250=250\). Adding these two net changes gives \(300+250=550\).

Therefore, option C, an increase of 550, is correct. Adding births, deaths, arrivals, and departures as positive values would count deaths and out-migration incorrectly. The correct balance can also be written as \(1200-900+500-250=550\). This is a change in population, not necessarily the final population, because the initial population has not been supplied.

Correct answer: D. Increase of 30000

Total population change is found by adding natural change and net migration. Since deaths exceed births by 50,000, natural change is \(-50,000\). Net in-migration of 80,000 is a positive change because more people enter than leave. Combining the two effects gives \(-50,000+80,000=+30,000\).

Therefore, option D is correct: the country’s total population increases by 30,000. The natural population process alone would produce a decline of 50,000, but immigration is larger than that decline and more than offsets it. Option A has the wrong sign, option B ignores migration, and option C counts the full migration without subtracting the natural decrease.

Correct answer: A. Decrease of 25000

Total population change includes both natural change and migration. Natural increase adds people because births exceed deaths. Net out-migration subtracts people because more residents leave than newcomers enter. To find the total, the signed effects must be combined rather than added as positive numbers. A negative result means that the population decreases overall.

Here the natural increase is +40,000 and net out-migration is −65,000. Therefore total change is \(40000-65000=-25000\). The province loses 25,000 people overall, even though births exceed deaths by 40,000. Hence option A, a decrease of 25,000, is correct. Adding the two magnitudes would incorrectly give 105,000 and ignore the direction of migration.

Correct answer: B. Natural increase will rise

Natural increase is the change in population caused by births and deaths, excluding migration. In rate form, it is commonly expressed as birth rate minus death rate: \(NI=BR-DR\). If the birth rate stays unchanged and improved health care lowers the death rate, the difference between the two rates becomes larger. More births are then occurring relative to deaths, so the population experiences a higher natural increase, assuming the rates are measured for the same population and period.

Option B is correct. Option A would be expected if the death rate rose or the birth rate fell, not when deaths decline while births remain constant. Natural increase does not automatically become zero, so C is incorrect. Migration is a separate component of population change; it may change independently, but the question asks about the effect of lower mortality, so D misses the main point. The increase may be temporary or vary in size, but its direction is upward under the stated conditions.

Correct answer: C. Population may still grow but more slowly

Natural increase depends on whether the birth rate is higher or lower than the death rate. Here the birth rate is declining, but it still remains above the death rate. Births therefore continue to exceed deaths, so the natural increase remains positive. The gap may become smaller, which means the population grows more slowly rather than immediately falling.

Option C is correct. A declining birth rate does not automatically mean a declining population; the comparison with the death rate is decisive. Option A ignores the continuing positive difference, while B wrongly says growth must accelerate. Option D also overlooks that a positive natural increase itself changes population, even before migration is considered.

Correct answer: D. Population is growing but more slowly than before

A growth rate describes the percentage change, not whether the population is increasing at all. A rate of 2 percent means faster growth than a rate of 1 percent, but both are positive. If the population changes by a positive 1 percent, the total number of people still increases; only the pace of increase has slowed.

Therefore, option D is correct. For instance, a population of one million would gain 20,000 at 2 percent but 10,000 at 1 percent, so it would still gain people in the second case. A stopped or declining population would require a zero or negative rate, respectively. Thus a lower positive rate must not be confused with population decline.

Correct answer: B. 100000

A growth rate of 2 percent means that two out of every hundred people in the initial population are added during the year, under the simple calculation requested. The population is 5 million, or 5,000,000. The increase is \(5000000\times(2/100)=100000\) people. Thus approximately 100,000 people will be added in one year.

Option B is correct. The answer is an increase, not the total population after one year; the total would be about 5.1 million under this simplified calculation. 50,000 represents only 1 percent of 5 million, while 200,000 represents 4 percent. The wording says to apply the rate simply, so there is no need to consider compounding, changing rates, migration separately, or exact demographic fluctuations.

Correct answer: C. The second country because its population base is larger

The number added by a percentage growth rate is found by multiplying the initial population by the rate. Equal rates therefore produce larger absolute increases in places with larger population bases. The percentage is the same, but the base to which it is applied is different.

For the first country, \(20000000\times0.01=200000\) people are added in one year. For the second, \(200000000\times0.01=2000000\) people are added. The second country therefore gains ten times as many people because its starting population is ten times larger. Hence, option C is correct.

Correct answer: B. 5 percent

Percentage growth is measured relative to the initial population, not the final population. The initial population is 800,000 and the final population is 840,000. First find the absolute increase: \(840000-800000=40000\). Then divide this increase by the initial value and multiply by 100: \(\frac{40000}{800000}\times100=5\) percent.

Therefore, option B is correct. The final population is 840,000, but it should not be used as the base for ordinary percentage growth from the original population. Using the initial population is important because the question asks how much the population grew from its starting level. The result says that for every 100 people initially, there are now 105.

Correct answer: C. 10 percent

Percentage growth over the whole period is calculated by comparing the total increase with the initial population. The initial population is 1.2 million, or 1,200,000, and the increase is 120,000. Therefore, the calculation is \(\frac{120000}{1200000}\times100=10\%\). The five-year duration does not change the total percentage calculation requested here.

Hence option C, 10 percent, is correct. Dividing the increase by five would help find an average absolute annual increase, but it would not be needed for the total percentage growth. Also, the question does not ask for a compound annual growth rate, which would require a different formula. The key is to use the increase as the numerator and the starting population as the denominator.

Correct answer: D. 3.3 million

A 10 percent increase means adding one-tenth of the original population. The initial population is 3 million, so the increase is \(3,000,000 \times 0.10 = 300,000\). The new population is found by adding this increase to the starting population, not by reporting the increase alone.

Thus, new population = \(3,000,000 + 300,000 = 3,300,000\), which is 3.3 million or 33 lakh. Therefore option D is correct. Option A is only the original population, while 3.1 million would represent an increase of just 100,000. The calculation confirms that ten percent of 3 million is 0.3 million.

Correct answer: A. 1 million

The final population is 10 percent greater than the initial population, so it represents 110 percent of the initial value. If the initial population is P, then the final population is \(1.10P\). Given a final population of 1.1 million, solve \(1.10P=1.1\) million. This gives \(P=1.1/1.10=1.0\) million, or 10 lakh. Therefore option A is correct.

It is important not to treat the final figure as the initial figure. The 10 percent increase is calculated from the initial population, not from the final population. A check confirms the answer: 10 percent of 1 million is 0.1 million, and adding it gives 1.1 million. Thus 9 lakh, 11 lakh, and 12.1 lakh do not satisfy the stated relationship.

Correct answer: B. It can be positive

Natural increase is the difference between births and deaths. If its rate is zero, births and deaths have approximately equal effects. Net migration is the difference between people entering and people leaving. A positive net migration rate means more people enter than leave. These incoming people add to the population even though natural increase is zero.

Therefore, option B is correct: the total growth rate can be positive. In a simple rate relationship, total population growth is approximately natural increase plus net migration. With natural increase equal to zero and net migration positive, the combined rate is positive, assuming the rates use compatible definitions and periods. It is not necessarily negative or zero, and migration clearly contributes to total population change.

Correct answer: B. 1 percent

Answer: B, 1 percent. Total population growth is found by combining natural increase with net migration: total growth rate = natural increase rate + net migration rate. Substitute the values: 1.5% + (−0.5%) = 1.0%. The negative migration rate means that net out-migration reduces the growth produced by births exceeding deaths. Option A is not obtained from the correct signed calculation. Option C ignores migration completely and uses only the natural increase rate. Option D adds the numerical magnitudes, but it wrongly treats negative migration as positive migration. Keep the minus sign attached to the migration rate throughout the calculation. Thus the country still grows, but only by 1 percent.

Correct answer: B. 20 per thousand

Natural increase per thousand is found by subtracting the death rate from the birth rate. This measures the change caused by births and deaths before considering migration. Here the birth rate is 28 per thousand and the death rate is 8 per thousand, so the difference is \(28-8=20\) per thousand.

Therefore option B is correct. A rate of 20 per thousand means that, without migration and under the stated rates, the population would gain about 20 people for every 1,000 people through natural increase during the relevant period. It is not 36 because the rates are subtracted, not added, and it is not 28 because deaths must be considered.

Correct answer: C. -5 per thousand

The natural increase rate is calculated by subtracting the death rate from the birth rate. Both rates are expressed per thousand, so their difference remains per thousand. A negative result means that deaths are more numerous than births, so the population decreases naturally before migration is considered.

Natural increase rate = birth rate − death rate = 18 − 23 = −5 per thousand. Therefore, option C is correct. The negative sign is essential: it shows a natural decrease of 5 persons per thousand, not an increase of 5. Adding the rates gives 41 per thousand, but that only represents their sum and is not the formula for natural increase. Migration is not included in this calculation.

Correct answer: C. 2 percent

A rate expressed per thousand tells how many units occur out of 1,000. A percentage tells how many occur out of 100. Since 1,000 is ten times 100, converting a per-thousand value to a percentage requires dividing the number by 10, or equivalently multiplying by 100 and dividing by 1,000.

For 20 per thousand, the calculation is \(20/1000\times100=2\) percent. Thus a natural increase rate of 20 per thousand is equal to 2 percent, making option C correct. The value is not 20 percent: 20 per thousand means 20 out of 1,000, whereas 20 percent means 20 out of 100 and is ten times larger.

Correct answer: A. Natural increase will slow

Natural increase is determined by the difference between the birth rate and the death rate. If this gap becomes smaller, the number or rate of people added through births beyond deaths also becomes smaller. Therefore, assuming migration and other factors do not change, the natural increase will slow down.

For example, a fall in the gap from 2 percent to 1 percent means that the population is being added naturally at a lower rate. This does not necessarily mean that the population immediately decreases; it means its natural growth becomes slower. Hence option A is correct. The population cannot be said to double immediately, and the narrowing gap clearly does affect natural increase.

Correct answer: D. A lower rate applied to a large and growing population base can still add many people

A growth rate is a percentage applied to the population base, whereas the number added is an absolute quantity. If the base population is very large and continues to grow, even a declining positive percentage can produce many additional people. Therefore, a lower rate does not necessarily mean that the yearly addition immediately becomes smaller.

For example, 2% of 100 million is 2 million, while 1.5% of 150 million is 2.25 million. The rate has fallen, but the number added has risen because the base is larger. Land area is not required to increase, and migration is not the main explanation in the stated case. Hence, option D is correct.

Correct answer: A. When a very large number of people are in reproductive ages

Demographic momentum occurs when a population has a large number of young people because of high fertility in the past. As this large group reaches reproductive ages, it can produce many births even if each woman has fewer children than earlier generations. The number of potential parents remains high, so total births may continue to exceed deaths for some time. Population growth can therefore persist after fertility begins to decline.

Option A is correct because a large reproductive-age population is the essential condition described. Equal age groups do not create the same momentum, and stopping births would end natural increase rather than continue it. A population with no young people would generally have weaker momentum. The effect is temporary and eventually weakens as smaller birth cohorts replace the large earlier cohorts.

Correct answer: A. Future growth potential may rise as many children enter reproductive ages

A high proportion of children creates population momentum. These children will gradually enter working and reproductive ages. Even if each future family has only moderate fertility, a large number of people reaching reproductive age can produce many births in total. The population may therefore continue growing for some time, even if fertility later begins to fall. The effect is about future potential, not an immediate guarantee.

Option A is correct. Age structure matters because it influences the number of people likely to have children in coming decades. A child-heavy population does not necessarily decline immediately, and age composition is not unrelated to growth. It is also incorrect to assume that all children will migrate. Future growth will additionally depend on fertility, mortality, migration, and social conditions.

Correct answer: B. Natural increase may be low or negative

Natural increase is the difference between births and deaths, without including migration. A very low birth rate means that relatively few new people are being added. If the elderly share is very large, the population may have more deaths because many people are in older age groups. These two conditions can make the difference between births and deaths small or even below zero.

Thus option B is correct: natural increase may be low or negative. It is not necessarily rapid, and it cannot always be exactly 10 percent. Age structure matters because it influences both the number of people likely to have children and the number exposed to older-age mortality. Migration could still make total population grow, but that would be net population change rather than natural increase. The answer concerns births minus deaths only.

Correct answer: A. High positive net migration

Population change equals natural increase plus net migration. When births and deaths are nearly equal, the natural increase is close to zero. If the city is nevertheless growing rapidly, another component must be adding many people. The most likely component is positive net migration, meaning more people move into the city than leave it.

Thus option A is correct. High out-migration would reduce population, while zero migration would leave only the small natural change. Increasing land area changes the denominator used for density but does not itself add residents. The question asks about population growth, so the relevant explanation is a large excess of in-migrants over out-migrants, including possible movement for jobs, education, or services.