# CBSE Class 7 Science Revision Notes Chapter 14

## CBSE Class 7 Science Revision Notes Chapter 14 – Electric Current And Its Effects

Science is an interesting subject to study and an easy subject to score marks on with the right efforts.

Class 7 Science Chapter 14 Notes deal with the chapter on electricity. The CBSE Syllabus introduces Class 7 students to the basic concepts only. Students need to study these concepts for understanding advanced concepts in higher classes. Extramarks provide detailed revision notes written by subject matter experts for students to clear any doubts and make learning concepts easier.

Class 7 Science Chapter 14 Notes discuss all the major concepts, which allows students to answer all of the Important Questions from the chapter. As these notes are available on the website, students can access them at their convenience.

### Electric Current’s Effects

When electricity runs through a wire, it shows mainly two effects: the heating effect and the magnetic effect.

• Heating Effect: Electricity heats up a wire when it travels through it from one end to another. It is called the heating effect of electricity. The amount of heat generated depends on several factors, such as the material of the wire, its length, and its thickness. When electricity travels through the coil of an electric heater called an element, it generates so much heat that it turns red hot.
• Fuse: A fuse is a small device easily found on the switchboards of every household that protects an electric circuit from the heating effect of electricity. It is created by inserting a thin wire into an insulating material.
• MCB: Miniature Circuit Breakers is abbreviated as MCB. These are advanced switches that turn off automatically when the current in the circuit reaches the safety limit.
• Magnetic Effect: Electricity creates a magnetic field around it when it runs through a wire. This is called the magnetic effect of electricity. Hans Christian Oersted was the first to observe this effect.
• One of the most widely used applications of this effect can be seen while creating an electromagnet. In this process, a lengthy insulated wire is wound around a rod of soft iron and the switch is turned on to allow the current to flow through it. The wire now acts as a magnet.
• Electromagnets are used to: a) separate magnetic material from garbage, b) remove small iron particles accidentally falling into the eyes, and c) make a variety of toys.

### Electric Current and Its Effects: Class 7 Science Chapter 14 Revision Notes Summary

The revision notes on Chapter 14: Electric Current and Its Effects explain the rudimentary concepts at first. They explain what a charge is, how it is formed, and the two types of charges, namely, positive and negative. Students will also learn that similar charges show a repelling effect, whereas opposite charges attract one another. These charges flow through a medium called a conductor and this flow of charge is known as electricity.

The notes then explain the different effects exhibited by electricity. Students have learnt that the sun is a source of heat, but now they will understand that electricity can also generate heat too when it runs through a conductor. The heat generated by the flow of electricity depends on various factors, which are briefly explained in the notes. After studying this section, students will be able to explain what conductors and insulators are, the differences between them, the applications of the effects shown by electricity and the factors responsible for generating heat in a wire.

The next section sheds light on how an electric bulb produces light. Students will learn how a filament works to produce light continuously and its features. This section further discusses how a fuse protects all electrical appliances from the damage caused by a sudden supply of high-voltage electricity. Class 7 Science Chapter 14 Notes are designed in such a way that they address every query of a student related to the chapter. By going through the notes, students will understand that the lightning in the sky is nothing but a flow of electrically charged particles.

The next section of the notes describes electromagnets and permanent magnets and their differences. Students will learn how electromagnets are used by doctors for treatment; and how their power can be controlled by using the induction effect of electricity. These revision notes are well-structured to help students understand the logical progression from one topic to another.

These are the basic concepts of electricity, which students must learn before studying advanced concepts. They must learn these topics very well and know when electricity can cause harm, and why they should never touch a conductor that is not insulated. Electricity is an indispensable part of modern life, but one should not play with it out of the fit of a playful adventure.

### 1. What are the advantages of using Class 7 Science Chapter 14 Notes from Extramarks?

The revision notes provided by Extramarks are prepared by subject matter experts who refer to the revised CBSE guidelines and syllabus. These notes are well-structured and comprehensive yet written in a concise manner. Students can refer to these notes to prepare for topics that are important from the exams’ perspective. They will grasp the concepts easily as they are illustrated with examples. With these notes, students can revise the entire chapter quickly and effectively.

### 2. What are the applications of electromagnets?

Electromagnets are made by wrapping an electricity-carrying conductor around a soft-core piece of an iron rod. The power of such magnets can be maintained by controlling the flow of current. These magnets are widely used by ophthalmologists for removing iron dust that falls into the eyes accidentally. The toy industry also uses electromagnets to make its products interesting. Moreover, electromagnets are also used for removing magnetic substances from the garbage.

### 3. What are the two main effects shown by the electric current?

Electricity shows certain effects when it flows through a wire. It heats up the wire and generates a magnetic field around it. These are called heating effects and magnetic effects respectively. These effects are widely used to make modern life easier. The electric heater that can be found in nearly every household utilises the heating effect. When electricity runs through its coiled wire, the heat generated turns it hot. Again, the usage of the magnetic effect is manifold. Students can refer to the Class 7 Science Chapter 14 Notes for further details.

### 4. What is meant by MCB?

The full form of MCB is Miniature Circuit Breakers, which is a special kind of switch that gets turned off if the electricity reaches the safety limit.