Electricity and Circuits:Class 6 Science NCERT Chapter 12

Key Features of NCERT Material for Class 6 Science Chapter 12 – Electricity and Circuits

In the previous chapter 11:Light,Shadows And Reflections, you have studied about how the light,shadows and reflections occur and forms.In this chapter: Electricity And Circuits, you will study about the flow of electricity,its components and some safety measures.

Quick revision notes

Power station: Electricity that we use at homes, in our factories, is provided from a power station. 

Electric cell: Electric cell is a wellspring of electricity. 

Production of electricity in a cell: An electric cell creates a small amount of electricity from chemicals put away inside it. At the point when the chemicals in the electric cells are spent, the electric cells quit producing electricity. 

Terminal: All sorts of electric cells have two terminals, a positive terminal and a negative terminal. In a dry cell utilized in our homes, the central carbon bar is the positive (+) terminal and the zinc contained is the negative (- ) terminal. 

Battery: When at least two cells are joined together, the combination is called a battery. 

Bulb: We get light from a thin tiny wire inside the glass spread. This is called filament. It is upheld by two thicker wires, as appeared in Fig. One of these thick wires is associated with the metal casing around the base of’the bulb. The other is associated with the metal tip of the base. The two terminals of the bulb are the base of the bulb and the metal tip of the base. These two terminals are fixed so as to not contact each other. 

The inside bit of the bulb is topped off with inert gases, similar to argon.

Circuit: The total path, from one terminal of the electric cell through the bulb and back to the next terminal of the electric cell, is called a circuit. 

 

Open circuit: If there is any gap in the path of a circuit, the bulb doesn’t illuminate. Such a circuit is called an open circuit. 

 

Closed circuit: The bulb illuminates just when a bulb and wire structure a total path, which starts at one terminal of electric cell and finishes at the other terminal. Such a circuit is called a closed circuit. 

 

Flow of current in a circuit: As soon as the path from one terminal of electric cell to the next is finished, an electric current starts flowing through the circuit and the bulb illuminates. The electric current flows from the positive terminal to its negative terminal of the electric cell . 

 

 

• In the bulb, current comes in through one of its terminals, goes through the filament inside the bulb and comes out through the other terminal of the bulb. 
• At the point when the current flows through the filament, it starts glowing. 
• Fused bulb: If the filament of the bulb is broken, the circuit isn’t corhpleted and thus the current cannot flow.  A fused bulb is the one with a broken filament. At the point when a bulb gets fused, it doesn’t illuminate. 
• Electric switch: Electric switch is a straightforward gadget that either breaks the circuit or finishes it to stop or start the flow of current. 
• At the point when the switch finishes the circuit, it is called closed switch. 
• At the point when the switch breaks the circuit, it is called open switch.

(Chapter – 12: Electricity and circuits)

Conductors 

 

Conductors refer to the materials through which electric current can flow. 

 

Most metals are conductors. 

 

Our body is also a decent conductor. 

Insulators 

 

Insulators are materials through which the electric current cannot pass. At the end of the day, insulators are the bad conductors of electricity. 

 

Elastic and wood are insulators. 

 

Conduction tester: It is a straightforward gadget to test whether a material is a conductor or insulator. 

 

 

Filament: The thin wire that radiates light is called the filament of the bulb. 

 

Dry cell: It is referred to a source of electricity. It generates direct current (DC) because of chemical reaction that takes place inside it. 

 

Bulb: An electric bulb is a gadget which gleams and discharges light, when electric current is passed through it. 

 

Conductors: The things that allow electric current to pass through them.

 

Electric cell: It is referred as a source of electricity. 

 

Electric circuit: The total path from one terminal of the electric cell through the bulb and back to other terminal of the electric cell is called an electric circuit. 

 

Filament: In electric bulb, there is a thin tiny wire inside the glass spread. This is called filament. 

 

Insulator: Materials that don’t allow electric current to pass through them are called insulators. 

 

Switch: Electric switch is a basic gadget that either breaks the circuit or finishes it to stop or start the flow of current. 

 

Terminal: All types of electric cells have two terminals, one is a positive terminal and another is a negative terminal. 

 

An existence without electricity is hard to imagine. Many gadgets and machines in our day-to-day life run on electricity. 

 

Take a gander at the photos given underneath. Which of these sudden spike in demand for electricity? Compose their names in the space gave. 

 

 

Things that sudden spike in demand for electricity have electric current passing through them. In this, chapter, you will learn about electric current, what is expected to create it, the conditions required to make an electric current flow, and the materials through which current can flow. You will learn some extremely interesting things like how to make a small bulb shine and how to make an electric switch. Answers: Refrigerator, Fan. 

(Chapter – 12: Electricity and circuits)

Electric Current 

 

The greater part of the gadgets and machines we utilize like an electric iron, broiler, room heater, refrigerator, ceiling fan or an electric bulb work when an electric current flows through them. 

 

::::::With assistance from an adult, see what is inside a transparent electric bulb (Fig. 14.1). Among different things, you will see that it has a thin filament (a thin metal wire). The filament is heated up when an electric current passes by it. It heats up so much that it begins to shine and give out light. 

 

Presently, we will learn what creates an electric current. 

(Chapter – 12: Electricity and circuits)

Source Of Electric Current

 

A gadget that can be utilized to create an electric current is called a source of electric current. Normal sources of electric current are cells and batteries (assortment of cells) which comes in various shapes and sizes (Fig. 14.2), and electric current that are in the plug points around the houses. An extremely helpful kind of cell which we utilize frequently is the dry cell. Because of a chemical reaction that takes place in cells and batteries, electric current is created. 

 

For large-scale production of electricity, flowing water or steam is utilized. 

 

The Dry Cell:

The Dry Cell: 

 

A dry cell is an advantageous source of electric current. The dry cell, as its name proposes, contains dry or semi-strong ingredients. 

 

A look inside a dry cell [Fig. 14.3(a and b)]. 

 

 

The dry cell has a paste consisting of ammonium chloride inside a zinc container. Inside, there is a cardboard container containing powdered manganese dioxide where carbon is placed. The cardboard container has minuscule ‘gaps’ in it (such materials are called permeable materials) through which a chemical reaction takes place between ammonium chloride paste and powdered manganese dioxide. A pole, usually carbon, with a metal cap is dunked into the manganese dioxide. The entire thing is then sealed (with just the metal cap sticking out), so the substance don’t spill out.

There are cells that can be recharged once they are drained. These are called secondary cells. They are utilized in cell phones, laptops, and car batteries. 

 

Nowadays, solar cells are being utilized in many applications. Solar cells use daylight to create electric current. Fig. 14.4 Some gadgets that take a shot at dry cell. 

 

Many calculators are powered with solar cells. Solar panels made up of solar cells are utilized to illuminate boulevards and many homes. 

(Chapter – 12: Electricity and circuits)

Flow Of Electric Current

• Three basic conditions (Fig. 14.5) are required for an electric current to flow. 
• A gadget used to create an electric current like cell, battery, or a fitting point acting as a source. 
• A wire made of a metal like copper, silver, or aluminum, which will allow electric current to flow through easily. 
• A whole circle (of the wire) running from one terminal of the source, through various appliances, back to the next terminal of the source. 
• 

(Chapter – 12: Electricity and circuits)

Making a Simple Electric Circuit:

At the point when we associate the terminals of a pencil cell (name given to the cell because of its shape) to a bulb using two wires, the bulb gleams. This happens because we give a path to the current to flow. An electric circuit is a path for an electric current to flow. 

 

In  the diagram14.6(a), one wire from the pencil cell is joined with the light bulb, while the other wire isn’t. The electric circuit isn’t finished here. In Figure 14.6(b), both the wires from the cell are associated with the light bulb. The electric circuit is finished in this case. Electric current flows just if there is a whole path or closed circuit starting from one terminal of the source, through the light bulb, to the next terminal of the source. Consequently, the bulb gleams in Figure 14.6(b) yet not in Figure 14.6(a). The circuit in Figure 14.6(a) isn’t finished. Thus, current cannot flow through the circuit and the bulb doesn’t shine. Such a circuit is called an open circuit. The circuit in Figure 14.6(b) is finished. Electric current flows through the circuit and, therefore, the bulb sparkles. Such a circuit is called a closed circuit. 

Electric current flows a particular way. The electric current flows from the positive terminal to the negative terminal of the electric cell in an electric circuit,. Figure 14.7 shows the course of flow of electric current in a circuit. 

Electric Switch

 

We utilize electric switches (Fig. 14.8) to put on or off the electrical gadgets and machines. However, do you know how it works? 

 

 

An electric switch is a gadget that is utilized to open or close an electric circuit. At the point when we open an electric circuit, the flow of electric current in the circuit stops [Fig. 14.9(a)]. Once the electric circuit is closed, the  electric current flows through it [Fig. 14.9(b)]. In an electrical circuit, a switch is now and then. 

(Chapter – 12: Electricity and circuits)

Electric Torch

 

A schematic diagram of an electric light is appeared in Fig. 14.10. An electric light has at least one dry cells inside it, which act as the ‘source’. These cells are associated through a switch to a small bulb. At the point when the switch is pushed to the ‘on’ position, the circuit is finished and the bulb gleams. At the point when the switch is pushed to the ‘off’ position, the circuit is incomplete (broken). Presently the current cannot flow through the circuit, and the light goes out. 

 

Conductors And Insulators

Take a gander at Figures 14.11(a)- (d). Each shows a total electric circuit. At that point can any anyone explain why the bulb gleams just in circuits (b) and (d)?The reason being: not all materials allow electric current to pass through them. 

 

A material that allows electric current to pass through it is called a conveyor of electricity like the key and the safety pin [Figs. 14.11(b) and (d)]. A material that doesn’t allow electric current to pass through it is called an insulator of electricity like the elastic band and the plastic pen [Figs. 14.11(a) and (c)]. 

 

All metals are conductors of electricity while some are preferred conductors over others. A couple non-metals like graphite (pencil lead is made of graphite) are also conductors of electricity. 

 

Examples of insulators are glass, wood, elastic, unadulterated water, and dry air. Flowever, the smallest debasement in water (polluting influences are substances like salts, broke up in water) makes it a conductor. 

 

The handles of screwdrivers and testers utilized by electricians are usually made of wood or hard plastic. They also wear elastic gloves while repairing an electric switch to avoid electric stun. 

(Chapter – 12: Electricity and circuits)

Electrical Safety

 

Electricity can be extremely dangerous, on the off chance that you don’t handle electrical gadgets carefully. One ought to never play with electrical wires and attachments. Electricity from cells is safe and you can try different things with it, however you have to be careful not to interface the two terminals of a cell legitimately through a wire/conveyor. Electricity generated by portable generators is dangerous and ought not be utilized for tests. 

 

Source of electric current: A gadget that can be utilized to deliver an electric current is called a source of electric current. 

 

Electric circuit: A way for an electric current to flow. 

 

Closed circuit: A circuit which has a ‘whole path’ through which an electric current can flow is called a closed circuit. 

 

Open circuit: A circuit consisting of a break in it is called an open circuit. 

 

Electric switch: A gadget that is utilized to open or close a circuit is called an electric switch. 

 

Conduit (in this chapter): A material that allows electric current to pass through it easily is called conveyor. 

 

Insulator (in this chapter): A material that doesn’t allow electric current to pass through it easily is called an insulator. 

 

In a dry cell, a chemical reaction takes place to create an electric current. 

 

A dry cell contains strong or semisolid ingredients. 

 

All cells consist of two terminals: the positive and the negative terminal. 

 

Electric current flows just if there is a solid or complete path, starting from one terminal of the source, through various gadgets back to the next terminal of the source. 

 

An electric switch is a gadget that is utilized to open or close a circuit.