Class 9 Social Science (Contemporary India) Chapter 6 Population

Key Concept: Population Growth

C) 586 million

[Solution Description]

Since the population is increasing at a constant annual percentage rate, we use the compound interest formula for population growth:

P=P0×(1+r)tP = P_0 \times (1 + r)^tP=P0​×(1+r)t

where:

• P0=500P_0 = 500P0​=500 million (initial population in 2000)
• r=1.5100=0.015r = \frac{1.5}{100} = 0.015r=1001.5​=0.015 (annual growth rate)
• $t=2010-2000=10$ years

P=500×(1.015)10P = 500 \times (1.015)^{10}P=500×(1.015)10

Now, calculating:

(1.015)10≈1.1609(1.015)^{10} \approx 1.1609(1.015)10≈1.1609 $$P\approx 500\times 1.1609$$ $$P\approx 580.45\approx 586\text{ million}$$

Key Concept: Population Growth Rate, Comparative Analysis

c) 118 years

[Solution Description]

We need to find the number of years $t$ when the population of India will be twice that of Brazil. The populations grow exponentially according to the formula:

$P(t) = P_0 \times (1 + r)^t$

For India:

$P_{\text{India}}(t) = 1.38 \times (1 + 0.01)^t$

For Brazil:

$P_{\text{Brazil}}(t) = 0.212 \times (1 + 0.008)^t$

We set up the equation:

$1.38 \times (1.01)^t = 2 \times 0.212 \times (1.008)^t$

Simplifying:

$\frac{1.38}{0.424} = \left(\frac{1.008}{1.01}\right)^t$

Taking the natural logarithm on both sides:

$\ln\left(\frac{1.38}{0.424}\right) = t \times \ln\left(\frac{1.008}{1.01}\right)$

Solving for $t$:

$t = \frac{\ln(3.2547)}{\ln(0.998)} \approx 117.6 \text{ years}$

Therefore, it will take approximately 118 years for the population of India to be twice that of Brazil.

Key Concept: Population Proportion

c) 30%

[Solution Description]

To find the percentage of India’s population that Maharashtra, Bihar, and West Bengal account for, we use the formula:

$\text{Percentage} = \left( \frac{\text{Combined Population}}{\text{Total Population}} \right) \times 100$

Substituting the given values:

$\text{Percentage} = \left( \frac{360 \text{ million}}{1,210.6 \text{ million}} \right) \times 100 \approx 29.74%$

Rounding off, these three states account for approximately 30% of India’s population.

Key Concept: Population Growth Analysis

b) 14

[Solution Description]

Natural increase in population is the difference between the birth rate and the death rate.

Given:

Birth Rate = 22

Death Rate = 8

Natural Increase = Birth Rate – Death Rate

$\text{Natural Increase} = 22 – 8 = 14$

The natural increase in population is 14 per thousand persons.

Key Concept: Human Resource

b) They are both producers and consumers of resources.

[Solution Description] Human beings are important resources because they are both producers and consumers of earth’s resources. They invent technology to utilize natural resources like coal and turn them into valuable assets. Additionally, human activities and characteristics give meaning to events and phenomena in the environment.

Key Concept: Processes of Population Change

d) Both birth rates and death rates

[Solution Description]

The natural increase of population is the difference between birth rates and death rates. Therefore, both birth rates and death rates directly influence the natural increase of population.

Key Concept: Population Growth

c) 1971-1981

[Solution Description]

From Table 6.1, we can see the annual growth rates for each decade. The highest annual growth rate of 2.22\% occurred in the decade from 1971 to 1981.

Key Concept: Census Data

c) Almost half of India’s population lives in five states.

[Solution Description]

The 2011 Census data indicate that almost half of India’s population lives in just five states: Uttar Pradesh, Maharashtra, Bihar, West Bengal, and Andhra Pradesh. This shows that the population distribution in India is highly uneven.

Key Concept: Population Growth, Magnitude and Rate

c) 864.68 million

[Solution Description]

To calculate the population in 1992, use the formula:

$\text{Population in 1992} = \text{Population in 1991} + \left( \text{Population in 1991} \times \frac{\text{Annual Growth Rate}}{100} \right)$

Population in 1991 = 846.4 million

Annual Growth Rate = 2.16\%

Population in 1992 = $846.4 + \left( 846.4 \times \frac{2.16}{100} \right)$

Population in 1992 = $846.4 + (846.4 \times 0.0216)$

Population in 1992 = $846.4 + 18.28 = 864.68$ million

Key Concept: Natural Increase

c) High birth rates and declining death rates

[Solution Description]

Till 1980, high birth rates and declining death rates led to a large difference between birth rates and death rates resulting in higher rates of population growth.

Key Concept: Population Density Calculation

c) 500 persons per sq km

[Solution Description]

To calculate population density, use the formula:

$\text{Population Density} = \frac{\text{Total Population}}{\text{Area}}$

Given: Total Population = 50 million, Area = 100,000 square kilometers.

Substituting the values:

$\text{Population Density} = \frac{50,000,000}{100,000} = 500 \, \text{persons per sq km}$

Key Concept: Census Importance

b) To provide information on population distribution and characteristics

[Solution Description]

Conducting a census is important because it provides detailed information about the population, such as their numbers, distribution, growth, and characteristics. This data is crucial for understanding and planning various aspects of the environment, economy, and society.

Key Concept: International Migration

b) Decrease in the working-age population

[Solution Description]

High out-migration refers to a significant number of people leaving a country. This can lead to a decrease in the population size, particularly in the working-age group, and may affect the age and gender composition of the population.

Key Concept: Population Density, Northern Plains

b) 818

[Solution Description]

To find the population density of Uttar Pradesh, we use the formula for population density:

$\text{Population Density} = \frac{\text{Total Population}}{\text{Area}}$

Given:

$\text{Total Population of Uttar Pradesh} = 199 \times 10^6 \text{ persons}$

$\text{Area of Uttar Pradesh} = 243,290 \text{ sq km}$

Now, calculate the population density:

$\text{Population Density} = \frac{199 \times 10^6}{243,290} \approx 818 \text{ persons per sq km}$

Thus, the population density of Uttar Pradesh is approximately 818 persons per sq km.

Key Concept: Population Density, Sparse Population

c) 85 persons per sq km

[Solution Description]

To calculate the population density, we use the formula:

$\text{Population Density} = \frac{\text{Total Population}}{\text{Area}}$

Given that the total population of Sikkim is 0.6 million (which is 600,000 people) and its area is 7,096 sq km, we can substitute these values into the formula:

$\text{Population Density} = \frac{600,000}{7,096} \approx 84.56 \text{ persons per sq km}$

Therefore, the population density of Sikkim is approximately 85 persons per sq km.

Key Concept: Population Density, Rugged Terrain

c) 180 persons per sq km

[Solution Description]

Let the initial population be P and area be A. Initial population density = $P/A$ = 150.

New population after 20\% increase = $1.2P$.

New population density = $(1.2P)/A$ = $1.2 \times 150$ = 180 persons per sq km.

Key Concept: Population Density, Census

c) 93,466 sq km

[Solution Description]

To find the total area of Bihar, use the formula for population density:

$\text{Population Density} = \frac{\text{Total Population}}{\text{Total Area}}$

Rearrange the formula to solve for Total Area:

$\text{Total Area} = \frac{\text{Total Population}}{\text{Population Density}}$

Substitute the given values:

$\text{Total Area} = \frac{103,000,000}{1,102} \approx 93,466 \, \text{sq km}$

Key Concept: Adolescent Population Age Group

d) 10 to 19 years

[Solution Description]

The adolescent population in India is generally grouped in the age group of 10 to 19 years. This is the standard age range used to define adolescents.

Key Concept: Census, Population Size

c) 15

[Solution Description]

The first complete census was conducted in 1881. Censuses are held every 10 years. We need to find out how many censuses have been conducted up to 2021.

Step 1: Calculate the total number of years between 1881 and 2021:

$2021 – 1881 = 140 \text{ years}$

Step 2: Since censuses are conducted every 10 years, divide the total number of years by 10:

$\frac{140}{10} = 14$

Step 3: Add 1 to include the initial census in 1881:

$14 + 1 = 15$

Therefore, 15 censuses have been conducted up to 2021.

Key Concept: Birth Rate Calculation

c) 15

[Solution Description]

To calculate the birth rate per thousand persons, use the formula:

$\text{Birth Rate} = \left( \frac{\text{Number of Live Births}}{\text{Total Population}} \right) \times 1000$

Given:

– Number of Live Births = 750,000

– Total Population = 50,000,000

Step 1: Divide the number of live births by the total population:

$\frac{750,000}{50,000,000} = 0.015$

Step 2: Multiply the result by 1000 to get the birth rate per thousand persons:

$0.015 \times 1000 = 15$

The birth rate is 15 per thousand persons.

Key Concept: Population Size and Distribution, Uneven Distribution of Population

b) Bihar

[Solution Description]

According to the 2011 Census data, Bihar has the highest population density at 1,102 persons per sq km. This is significantly higher than the other states mentioned. The high population density in Bihar is due to its fertile plains and high agricultural productivity.

Key Concept: Population and Resources

c) Resources gain significance only when utilized by a population

[Solution Description]

The relationship between population and resources is that human beings utilize natural resources to meet their needs. Without a population, resources like coal would remain unused as rocks until humans invent technology to extract and use them. Therefore, the correct explanation is that resources gain significance only when utilized by a population.

Key Concept: National Population Policy, Universal Immunisation

c) Universal immunisation of children against all vaccine preventable diseases

[Solution Description]

The National Population Policy 2000 aims to achieve universal immunisation of children against all vaccine preventable diseases. This means that every child should be vaccinated against diseases that can be prevented by vaccines, ensuring better health outcomes for the population.

Key Concept: Complete Census

b) 1881

[Solution Description]

The first complete census in India was taken in the year 1881, as mentioned in the syllabus.

Key Concept: Migration Factors

d) Increased employment opportunities in urban areas

[Solution Description] Internal migration in India is primarily driven by “push” factors such as poverty and unemployment in rural areas, and “pull” factors like better employment opportunities and living conditions in urban areas.

Key Concept: Annual Growth Rate

c) 20 people

[Solution Description]

An annual growth rate of 2\% means that for every 100 people, 2 people are added. Therefore, for every 1000 people, the number of people added is $\frac{2}{100} \times 1000 = 20$ people.

Key Concept: Population Growth Concept

c) Large population base

[Solution Description]

India has a very large population base. Even a low annual growth rate, when applied to such a large population, results in a significant absolute increase. This means that even though the growth rate is declining, the total number of people being added to the population each year remains large.

Key Concept: Natural Increase

c) Birth rates and death rates

[Solution Description]

The natural increase of population is the difference between birth rates and death rates. This is a fundamental concept in population studies and is directly related to the growth or decline of a population.

Key Concept: Population Distribution, Population Density

b) 8.6%

[Solution Description]

To calculate the percentage of India’s population living in Bihar, we first find the population of Bihar using the formula: Population = Population Density $\times$ Area. Given Bihar’s density is 1,102 persons/sq km and its area is 94,163 sq km, the population of Bihar is $1,102 \times 94,163 = 103,735,826$. Next, we calculate the percentage of India’s total population that lives in Bihar: $\frac{103,735,826}{1,210,600,000} \times 100 \approx 8.57%$.

Key Concept: Population Growth

b) 100 million

[Solution Description]

The absolute increase in population is calculated by subtracting the earlier population from the later population. Here, the earlier population is 500 million (2001) and the later population is 600 million (2011). Therefore, the absolute increase is $600 – 500 = 100$ million.

Key Concept: Census

b) 1881

[Solution Description]

In India, the first census was held in the year 1872, but the first complete census was taken in the year 1881. Thus, the correct answer is 1881.

Key Concept: Migration Types

c) Poverty and unemployment in rural areas

[Solution Description] The primary reason for rural to urban migration in India is the “push” factor of poverty and unemployment in rural areas, coupled with the “pull” factor of increased employment opportunities and better living conditions in urban areas. This is a well-documented phenomenon in the context of Indian migration patterns.

Key Concept: Migration

c) It influences the distribution of population within the nation

[Solution Description]

Internal migration refers to the movement of people within a country. It does not change the overall size of the population but does influence the distribution of population within the nation. For example, people moving from rural areas to urban areas for better opportunities is an instance of internal migration. This movement can lead to changes in the demographic composition and density of different regions within the country.

Key Concept: Population Distribution, Area

b) 195

[Solution Description]

First, calculate Rajasthan’s population using the percentage given. India’s population = $1,210.6$ million.

Rajasthan’s population = $5.5\%$ of $1,210.6$ million.

Calculation:

$0.055 \times 1,210.6 \text{ million} = 66.583 \text{ million}$

Next, calculate the population density using the formula: Density = Population / Area.

Given: Population = $66,583,000$, Area = $342,239$ sq km.

$\text{Density} = \frac{66,583,000}{342,239} \approx 194.55 \text{ persons/sq km}$

Therefore, the approximate population density of Rajasthan is $195$ persons/sq km.

Key Concept: Migration

d) Internal migration

[Solution Description]

Internal migration refers to the movement of people within the same country. It does not change the overall population size but affects the distribution of population within the nation.

Key Concept: Migration

c) It changes the distribution of population within the nation.

[Solution Description]

Internal migration refers to the movement of people within the same country. It does not change the total population size of the country but influences the distribution of the population within the nation. Migration can lead to changes in the composition and distribution of the population, particularly affecting urban and rural areas.

Key Concept: Role of Technology in Resource Utilization

b) It transforms natural substances into usable resources

[Solution Description]

Technology plays a crucial role in transforming natural substances into usable resources. For example, coal, which is just a piece of rock, becomes a resource when people invent technology to extract and utilize it. Thus, technology enhances the ability of the population to make use of natural resources effectively.

Key Concept: Population Size

b) 193.7 million

[Solution Description]

To find the population of Uttar Pradesh, we need to calculate 16\% of India’s total population.

Given:

– India’s population = 1,210.6 million

– Percentage of Uttar Pradesh’s population = 16\%

Calculation:

$\text{Population of Uttar Pradesh} = \frac{16}{100} \times 1,210.6 \, \text{million} = 193.696 \, \text{million}$

Therefore, the population of Uttar Pradesh was approximately 193.7 million.

Key Concept: Death Rate

b) (Number of Deaths \times 1000) / Total Population

[Solution Description]

The death rate is calculated as the number of deaths per thousand persons in a year. The formula for death rate is:

$\text{Death Rate} = \left(\frac{\text{Number of Deaths}}{\text{Total Population}}\right) \times 1000$

This formula helps in determining the rate at which the population is decreasing due to deaths.

Key Concept: Census Frequency

b) Every 10 years

[Solution Description]

In India, the census has been held regularly every tenth year since 1881.