CBSE Class 8 Science Exemplar Chapter 15: Some Natural Phenomena NCERT Solutions

Reviewed by · Updated on

NCERT Solutions PDF Class 8 PDF

This chapter, 'Some Natural Phenomena,' delves into fascinating and powerful events that shape our planet. The NCERT Solutions for Class 8 Science Exemplar cover key concepts such as electroscopes, electrical conductors and insulators, and the causes of natural disasters like earthquakes and tsunamis. Students will learn about the movement of the Earth's plates and how different types of charges interact. These solutions provide clear explanations and step-by-step reasoning, making complex topics accessible. They are designed to help students grasp the fundamental principles of these natural phenomena, reinforcing their understanding and aiding in effective exam revision by clarifying the underlying scientific principles and common misconceptions.

Home

Quick info

BoardCBSE
ClassClass 8
SubjectScience Exemplar
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 15

Chapter summary

Chapter 15 of the Class 8 Science Exemplar focuses on 'Some Natural Phenomena.' The NCERT Solutions provided here explain the working of an electroscope for detecting electric charge, differentiate between electrical conductors and insulators, and detail the causes of earthquakes, such as the movement of Earth's tectonic plates. It also touches upon the factors that can trigger tsunamis and the interaction between charged objects. These solutions aim to build a solid understanding of these natural events.

Learning outcomes

  • Understand the function of an electroscope in detecting electric charge.
  • Differentiate between electrical conductors and insulators.
  • Explain the causes of earthquakes due to the movement of Earth's tectonic plates.
  • Identify the phenomena that can cause tsunamis.
  • Describe the interaction (attraction and repulsion) between charged objects.

Topics covered

Paper topics

  • Electroscope
  • Electric Charge
  • Conductors
  • Insulators
  • Earthquakes
  • Tectonic Plates
  • Tsunamis
  • Charge Interaction
  • Natural Phenomena

Important topics

  • Causes of Earthquakes
  • Electroscope Function
  • Conductors vs. Insulators
  • Tsunami Triggers
  • Interaction of Charges

PDF preview

Read page by page below. PDF is streamed from the official NCERT website — no download button on this page.

Loading document …
Page of
Loading page …

Questions and Solutions

Multiple Choice Questions - 1

An electroscope is a device which is used to find if an object is
  1. charged
  2. magnetic
  3. free of cracks
  4. hot
Solution: The correct option is (a) charged. An electroscope is a scientific instrument designed specifically to detect the presence and sign of electric charge on a nearby object. It typically consists of two thin, lightweight metallic leaves or foils suspended in a way that they can move freely. When a charged object is brought near the electroscope, charge is induced on the leaves, causing them to repel each other and diverge, indicating the presence of a charge. The degree of divergence can sometimes give an indication of the magnitude of the charge.

Multiple Choice Questions - 2

Electric current is to be passed from one body to another. For this purpose the two bodies must be joined by
  1. cotton thread
  2. plastic string
  3. copper wire
  4. rubber band
Solution: The correct option is (c) copper wire. To pass electric current effectively from one body to another, the connecting material must be a good conductor of electricity. Copper is an excellent electrical conductor due to its atomic structure, which allows electrons to move freely. Cotton thread, plastic string, and rubber bands are all examples of electrical insulators; they resist the flow of electric current and are therefore unsuitable for this purpose.

Multiple Choice Questions - 3

The movement of the earth's plates causes
  1. cyclones
  2. lightning
  3. earthquakes
  4. thunderstorms
Solution: The correct option is (c) earthquakes. The Earth's crust is made up of large, rigid pieces called tectonic plates that are constantly moving. When these plates interact – by sliding past each other, colliding, or pulling apart – they can cause sudden tremors or shaking of the ground, which we experience as earthquakes. Cyclones, lightning, and thunderstorms are atmospheric phenomena, not directly caused by the movement of Earth's plates.

Multiple Choice Questions - 4

Two charged objects are brought close to each other. Choose the most appropriate statement from the following options:
  1. they may attract
  2. they may repel
  3. they may attract or repel depending on the type of charges they carry
  4. there will be no effect
Solution: The most appropriate statement is (c) they may attract or repel depending on the type of charges they carry. This is a fundamental principle of electrostatics. Objects with like charges (both positive or both negative) exert a repulsive force on each other, pushing them apart. Objects with unlike charges (one positive and one negative) exert an attractive force on each other, pulling them together.

Multiple Choice Questions - 5

Which of the following is not likely to cause Tsunami?
  1. A major nuclear explosion under sea
  2. Earthquake
  3. Volcanic eruption
  4. Lightning
Solution: The correct option is (d) Lightning. Tsunamis are large, powerful ocean waves typically generated by sudden, large-scale disturbances of the seabed or the water column. These disturbances are most commonly caused by underwater earthquakes, volcanic eruptions, or significant underwater landslides or explosions. Lightning is an atmospheric electrical discharge and does not have the capacity to displace the massive volume of water required to initiate a tsunami.

Multiple Choice Questions - 6

The earth's plate responsible for causing earthquakes is
  1. the crust of the earth
  2. the mantle of the earth
  3. the inner core of the earth
  4. the outer core of the earth
Solution: The correct option is (a) the crust of the earth. Earthquakes are vibrations that travel through the Earth's layers and are typically caused by the sudden movement or breaking of rocks within the Earth's crust. The crust is the outermost solid shell of a rocky planet, dwarf planet, or natural satellite. While the mantle and core are crucial parts of Earth's structure, the direct cause of most earthquakes is the stress and strain accumulating and releasing along faults within the crust.

Common mistakes

  • Confusing conductors with insulators.
  • Misidentifying the primary cause of tsunamis.
  • Not understanding that like charges repel and unlike charges attract.

Revision tips

  • Review the definition and use of an electroscope.
  • Memorize examples of good conductors and insulators.
  • Focus on the link between tectonic plate movement and earthquakes.
  • Understand the conditions that lead to tsunamis.

Practice MCQs

Q1. What is the primary function of an electroscope?

Q2. Which material is most suitable for joining two bodies to pass electric current between them?

Q3. What natural event is primarily caused by the movement and interaction of the Earth's tectonic plates?

Q4. When two charged objects are brought near each other, what is the most accurate description of their interaction?

Q5. Which of the following is LEAST likely to trigger a Tsunami?

Q6. The part of the Earth primarily responsible for causing earthquakes is:

Frequently asked questions

What is an electroscope and what does it do?

An electroscope is a device used to detect whether an object is electrically charged. It typically consists of two thin metallic strips that repel each other when charged.

Why is copper used to pass electric current between bodies?

Copper is used because it is a good conductor of electricity, meaning it allows electric current to flow through it easily. Materials like plastic and rubber are insulators and do not allow current to pass.

What causes earthquakes?

Earthquakes are primarily caused by the movement and sudden release of energy from the tectonic plates that make up the Earth's crust.

Can lightning cause a tsunami?

No, lightning is an atmospheric phenomenon and is not powerful enough to cause the underwater disturbances required to generate a tsunami.

How do charged objects interact with each other?

Charged objects can either attract or repel each other. Like charges (positive-positive or negative-negative) repel, while unlike charges (positive-negative) attract.

Which layer of the Earth is most associated with causing earthquakes?

The crust of the Earth, which is the outermost layer, is where the disturbances leading to earthquakes typically occur.

Important links

Content reviewed by the NCERT Help team. Editorial Team and update policy

NCERT Solutions PDF PDF on NCERT Help. URL unchanged for search indexing.