# Selina Solutions for Class 9 Physics Chapter 6 - Heat and Energy

Selina Solutions for Class 9 Physics Chapter 6 Heat and energy aims at presenting students of class 9 with a complete set of answers for all the textbook questions. These ICSE Class 9 Physics Selina solutions are framed in such a way that students understand the underlying concepts in-depth, this way students are assured to answer any type of question appearing in examinations.

Selina solutions are one of the best publishers for ICSE textbooks, continuously aiming at enriching students with the best and the latest in the field of science and mathematics. This endeavour of achieving excellence and nothing less makes Selina solutions students’ favourite.

We at BYJU’S provide ICSE Class 9 students with an outstanding study material after thorough research. The solutions have been framed by experts possessing substantial knowledge in the respective subjects, designed in-sync with the answering methodology expected in the examination.

## Selina Solutions for class 9 Physics Chapter 6 – Heat and Energy

ICSE Class 9 Physics 6 – Heat and energy chapter provides students of class 9 with insights around the concepts of heat and temperature. Heat is a spontaneous flow of energy from one body to another due to a temperature difference between them while the temperature is a quantity which states the thermal condition of a body.

This chapter discusses the various concepts revolving around ‘heat’, its definition, examples, units along with an understanding of differences between the concepts of heat and temperature as they are often misinterpreted.

Students in this chapter can also look forward to experiments demonstrating the behaviour of water at different temperatures. One of the other parts of the chapter enlightens students with information on energy sources, different types of energy sources along with examples.

List of subtopics covered in Chapter 6 – Heat and Energy

 Number Subtopic 6.1 Concept of heat 6.2 Concept of temperature 6.3 Thermal expansion 6.4 Anomalous expansion of water 6.5 Hope’s experiment to demonstrate the anomalous expansion of water 6.6 Consequences of anomalous expansion of water 6.7 Energy flow in an ecosystem 6.8 Applications of laws of thermodynamics in energy flow 6.9 Sources of energy 6.10 Renewable or non-conventional sources of energy 6.11 Non-renewable or conventional sources of energy 6.12 Judicious use of energy 6.13 Production of electricity from solar energy 6.14 Production of electricity from wind energy 6.15 Production of electricity from water energy 6.16 Production of electricity from nuclear energy 6.17 Energy degradation 6.18 Greenhouse effect 6.19 Global warming 6.20 Ways to minimize the impact of global warming

List of Exercise

 Name of the exercise Number of questions Page number Exercise-6A 23 129 Exercise-6B 16 132 Exercise-6C 24 141 Exercise-6D 20 145

## Selina Solutions for class 9 Physics Chapter 6 – Heat and Energy

Heat and energy is the 6th chapter that is covered in the class 9 physics textbook. The chapter provides an elaborate explanation for various concepts under heat and energy. Heat is a form of energy. Concept of temperature, its unit, and thermal expansion are explained with suitable graphs and examples so that students understand the theory.

Expansion of water when it is cooled from 4-degree Celsius to 0 degree Celsius is known as anomalous expansion of water. This concept has been explained with an experiment to practically demonstrate the concept, hence comprehend better.

The chapter also discusses energy and the flow of energy in an ecosystem, through the topic – food chain. The last part of the chapter deals with energy sources and the different types of energy. Energy is used in different forms, from different sources. The chapter briefs students about the various applications of energy sources.

### Key Features of Selina Solutions for class 9 Physics Chapter 6 – Heat and Energy

• Selina solutions are framed using a simple language and easy to understand terminologies
• Solutions are elaborate, explained along with suitable examples
• Use of relevant analogies makes it easier for students to understand
• Self-explanatory diagrams provided wherever necessary
• Solutions are unambiguous and completely reliable

## Frequently Asked Questions on Heat and energy

Q1

### What is heat?

Heat is the internal energy of molecules constituting the body. It flows from a hot body to a cold body. The S.I. unit of heat is the joule (J).

Q2

### S.I. unit of heat?

The S.I. unit of heat is joule (J).

Q3

### Name two substances which expand on heating?

The two substances that expand on heating are:

• Brass
• Iron
Q4

### What do you mean by anomalous expansion of water?

It is the expansion of water when it is cooled from 4â„ƒ to 0â„ƒ.

Q5

### What is an ecosystem?

It is a unit composed of biotic components (consumers, producers) and abiotic components (heat, rain, humidity).

Q6

### What is the source of energy for all ecosystems?

The most significant source of energy for all ecosystems is the Sun.

Q7

### What is a food chain?

A food chain demonstrates the feeding or nourishing relationship that is shared between varied living entities in a specific habitat or environment. The food chain begins with producers, that synthesize their own food by using energy from the Sun. Next in the chain, are the primary consumers (herbivores) that depend on producers for their nutritional requirements. Food chain is a series of events, depicting the energy flow from the Sun to the producers, from the consumers to the decomposers.

Q8

### Sun is renewable energy or non-renewable energy?

It is a renewable energy.