NCERT Solutions for Class 8th Social Science Chapter 13 Dynamics of Population
Updated on 2026-09-19
About this chapter
Demography is the study of the composition of a human population — age, sex, education, occupation, religion — and of how it changes over time through births, deaths and the movement of people. Governments use it to plan schools, hospitals, roads, housing, water, energy and waste services; businesses use it to work out who their customers are. India’s census , held about every 10 years, is the official count. Four indicators drive everything else (Fig. 6.7): the birth rate (live births per 1,000 people in a year), the fertility rate (average number of children a woman would have in her lifetime), the death or mortality rate (deaths per 1,000 people in a year) and migration . A fertility rate of 2.1 is the replacement level: above it a population grows, below it it eventually shrinks. World
- Chapter opener
- What Is Demography?
- Population at a Glance
- Birth and fertility rates
- Birth and fertility rates (Fig. 6.11)
- Migration
- Improvement in India’s sex ratio
- India’s Demographic Dividend
- End of chapter
Quick revision
| Term | What it means | Where the chapter uses it | Number to remember |
|---|---|---|---|
| Demography | The study of the composition of a human population — age, sex, occupation, religion — and how it changes over time | “What Is Demography?”, p. 168 | Three components: size; structure and composition; pattern and trend (Fig. 6.2) |
| Census | The official count of everyone in a country at a particular time, recording age, gender, marital status, education, language, religion, occupation and income | DON’T MISS OUT, p. 169 | India conducts one about every 10 years |
| Birth rate | The number of live births per 1,000 people in a year | Fig. 6.7, p. 172 | Measured per 1,000 people, per year |
| Fertility rate | The average number of children a woman would have in her lifetime | “Birth and fertility rates”, p. 173 | India: 5.7 in 1950 → 1.9 in 2025 |
| Replacement level fertility | The fertility rate at which children exactly replace their parents, keeping the population stable | p. 173 | 2.1 — not 2.0 |
| Death or mortality rate | The number of deaths per 1,000 people in a year; child mortality counts deaths under age 5 per 1,000 live births | “Death or mortality rate”, p. 176 | India’s child mortality: 271 per 1,000 (1950) → 28 (2023) |
| Life expectancy at birth | The average number of years a newborn is expected to live under today’s health, safety and living conditions | p. 176 | India: 30 years at Independence → 70 years in 2024 |
| Migration | Movement of people from one place to another, within or outside a country, to settle temporarily or permanently | “Migration”, p. 176 | Grew Delhi, Mumbai and Bengaluru |
| Demographic transition | The three-stage sequence of birth and death rates a country passes through as it develops | Fig. 6.12, p. 177 | Stage 1 both high · Stage 2 deaths fall · Stage 3 births fall |
| Sex ratio | The number of females per 1,000 males in a population | “Improvement in India’s sex ratio”, p. 180 | 933 (Census 2001) → 943 (Census 2011); women were 48.5% of the population |
| Population pyramid | A graph of a population by age group and gender, males on one side and females on the other; also called a population structure diagram | Fig. 6.15, p. 181 | Wide base = young and growing; wide top = ageing |
| Demographic dividend | The economic growth potential of a nation resulting from a younger and productive age structure | p. 184 | Nearly 65% of Indians are 15–59; median age 28 against Japan’s 50 |
Exercises
- Chapter opener — The Big Questions Page 167
- What Is Demography? — In-text Questions Page 168
- Population at a Glance — LET’S EXPLORE Page 172
- Birth and fertility rates — LET’S EXPLORE Page 173
- Birth and fertility rates (Fig. 6.11) — LET’S EXPLORE Page 175
- Migration — THINK ABOUT IT Page 177
- Improvement in India’s sex ratio — LET’S EXPLORE Page 180
- India’s Demographic Dividend — THINK ABOUT IT Page 183
- India’s Demographic Dividend — THINK ABOUT IT Page 186
- End of chapter — Questions and activities Page 187–190