Here we have given NCERT Class 7 Science Notes Chapter 14 Electric Current and Its Effects. To make sure that we buy good quality MCBs, we should look for ISI mark on them. When an electric current is passed through a high resistance wire (like nichrome wire), the resistance wire becomes hot and produces heat. If due to some reason, the current in household wiring suddenly becomes too large (and exceeds the safe limit), then the fuse will blow off (its wire will get heated too much, melt and break the circuit). In household electric wiring, electric current is supplied through two insulated wires which run together and reach each and every electrical appliance. These days MCBs, (miniature circuit breakers) are being used increasingly in household electrical switch. Question 4 What will happen if fuse is not inserted in household electric wiring? This will. So, the filament-type electric bulbs are not. has less resistance whereas a long wire has more resistance. Your email address will not be published. These days MCBs (miniature circuit breakers) are being used increasingly in household electrical switch in place of traditional fuses. MCB works on the magnetic effect of current. so if the same electric current is passed through a nichrome wire, then the heat produced in it will be too. MCB is a special kind of electrical switch which automatically turns off when the current in the circuit becomes too large, and cuts off the electricity supply. This is known as overloading. However, if an excess of current is passed through a wire it can melt or break. The two ends of the fuse wire are connected to these metal caps. The nichrome, wire has become hot because the electric current passing through. It, consists of a glass tube having a thin fuse, wire sealed inside it. A fuse works on the heating effect of current. consume much less electricity), and they also last much longer. An electric current can produce three effects: The degree to which a material opposes the passage of current through itself is called its resistance. much (due to which it will become very hot). A fluorescent tube light (or lamp) contains mercury vapour. The ISI mark ensures that the appliance is safe and energy efficient (the wastage of energy being the minimum). You can download Free Heating Effects of Electric Current Class 7 Video | EduRev pdf from By continuing, I agree that I am at least 13 years old and have read and agree to the. If the circuit is complete, the current flows. There are various day-to-day benefits of these electric current effects such as heating water, electrolysis, electroplating and electromagnets are just a few. MCB does not work on the heating effect of current. appliance is safe and energy efficient (the wastage of energy being the minimum). A fuse consists of a short length of a thin, tin-plated copper wire having low melting point. This prevents fire in the house (which could be, caused due to overheating of wires), and also prevents, damage to various electrical appliances (like TV and. In household electric wiring, electric current is supplied through two insulated wires, which run together and reach each and every electrical appliance. MCB can be re-set in the on position when the fault in the wiring (which caused a large current to flow in the circuit) has been set right. Choose the correct option. This is called the heating effect of current. is produced in the connecting wires of copper because copper has very low resistance. (3) Make an electric circuit by connecting the two nails to the two terminals of. This is because the fine tungsten filament has very high resistance whereas copper connecting wires have very low resistance. The bar acts like a magnet when around an iron bar electric current runs through a wire. electrical appliances such as TV and refrigerator could also damage them. Switch on the current. Let us find out. Electric fuses are inserted in the wiring (or circuits) of, connected in the household circuit The fuse grip has a, fuse wire fixed in it. The filament of an electric bulb has a high resistance.When electric current passes through the very thin, high resistance filament of an electric bulb, heat is produced in it. The thin fuse wire has a much greater resistance than the rest of the electric wiring in the house. protect the appliance from damage which could have been caused if the large current had passed through it. is called heating element of the appliance. Name two electric devices for each where (a) heating effect of current is used and (b) magnetic effect of current is used. on EduRev, you can check out Class 7 lecture & lessons summary in the same course for Class 7 Syllabus. For example : Copper has a very low resistance, so if electric current is passed through a copper wire, then the heat produced in it will be extremely small (due to which the copper wire will become negligibly hot). contains mercury vapour. important applications of the heating effect of current are given below: (1) The heating effect of electric current is utilised in the working of electrical heating appliances such. cell through a switch by using copper wires. Ques 3: Write two special characteristics of the wire needed for making the ‘element’ of an electric heater. This is because, the fine tungsten filament has very high resistance whereas copper connecting wires have very, bulb is not desirable because it leads to the wastage of electricity. Heating effect of electric current is used in (a) Electric watch (b) Bread toaster (c) Switch (d) None of these (b) Bread toaster. Thus, generation of heat by electric current while passing through a conductor is an inevitable consequence. This is called heating effect of electric current. has produced heat in it. Q13. When electric current is passed through an electric heating appliance by connecting it to a power socket through, insulated copper wires (called cord’ or ‘connecting cable’), then a large amount of heat is produced in the heating element (or coil) due to which the heating element become. MCB works on the magnetic effect of current. (a) Battery, (b) Switch 3. Practical application of heating effect of current. Devices Which Work on Heating Effect of Electric Current: Incandescent bulb is an example of a device which works because of the heating effect of electric current. traditional, filament-type electric bulbs). Due to this the filament of electric bulb gets heated to a very high temperature and start, electricity consumed by the filament of an electric bulb appears as heat due to which the glowing electric bulb becomes, quite hot.We should never touch a glowing electric bulb connected to the mains electricity. (2) Magnitude of current passed through the wire. (2) The heating effect of electric current is utilised in electric bulbs (or electric lamps) for producing light. This is the heating effect of current. This will protect the appliance from damage which could have been caused if the large current had passed through it. When an electric current flows through a wire, the wire gets hot. extremely large current from the household circuit. Can you think of any electric appliance where the heating effect of the electric current is used? The ISI mark ensures that the. This prevents the electric fires. If you The two ends of the fuse wire are, connected to these metal caps. Make a list of such appliances. The element, becomes red-hot because a lot of heat is produced in it on passing current (because of the high resistance, of nichrome coil). I really loved the way you explained the complicated subject in a clear and simple way. in place of traditional fuses. Activity - Make an electric circuit as shown in the figure. The elements of electric heating appliances (such as electric, om heater, electric iron, etc.) Author of this website, Mrs Shilpi Nagpal is MSc (Hons, Chemistry) and BSc (Hons, Chemistry) from Delhi University, B.Ed (I. P. University) and has many years of experience in teaching. When the live wire and neutral wire touch each other directly, then large current flows through the household wiring. Nichrome has a very high resistance so if the same electric current is passed through a nichrome wire, then the heat produced in it will be too much (due to which it will become very hot).The elements of electric heating appliances (such as electric room heater, electric iron, etc.) Similarly, when electric current is passed into an electric iron, the element of electric iron (made of nichrome coil) becomes red-hot and produces heat. EduRev is like a wikipedia just for education and the Heating Effects of Electric Current Class 7 Video | EduRev images and diagram are even better than Byjus! When the fuse grip carrying fuse wire is inserted in the fuse holder, then the circuit of household wiring is completed. Question 3 Explain why filament type electric bulb are not power efficient? Question 7 Give few applications of heating effect of current? The wire gets hot when an electric current passes through it. The values showed by Pinki here is a great concern and love towards her own 4 years old daughter. When electric current is passed through a conductor, it generates heat due to the resistance it offers to the current flow. MCQ Questions for Class 7 Science with Answers were prepared based on the latest exam pattern. The inside of glass tube is coated with an opaque, white, through it, the mercury vapour emits invisible ultraviolet, radiations and glows (or fluoresces) to emit white light. 3)Directly proportional to time for which electric current flow through conductor. work on the heating effect of current. All the electric heating appliances contain coils of high resistance wire made of alloy. Such connecting cables should be replaced immediately, When too many electrical appliances are connected to a single socket, they draw an. Question 11 Explain the working of electric bulb? (3)The heating effect of electric current is utilised in a safety device called ‘electric fuse’. Explore more by downloading Electric Current and its Effects Class 7 Notes on BYJU’S. Due to this the filament of electric bulb gets heated to a very high temperature and start glowing. The heating elements of most of the electric heating appliances (such as electric iron, electric kettle, electric geyser, electric oven, hotplates and hair dryers, etc.) Question 6 When does an electric short circuit occur? When electric current is passed through an electric heating appliance by connecting it to a power socket through insulated copper wires (called cord’ or ‘connecting cable’), then a large amount of heat is produced in the heating element (or coil) due to which the heating element become red-hot. This is the heating effect of the electric current. You can also find Heating Effects of Electric Current Class 7 Video | EduRev ppt and other Class 7 slides as well. When a switch is in OFF position, (i) circuit starting from the positive terminal of the cell stops at the … We should not use a thick wire as a fuse wire because it will have a low resistance and hence it will not get heated to its melting point easily. EduRev by using search above. If not, you may try it out now.Paheli and Boojho had also set up the game by connecting an electric circuit as suggested in Class VI. (2) Take about 10 centimetre long piece of nichrome wire and tie it between the two nails. The cord of heater made of copper does not become red-hot or, low because a negligible heat is produced in it on passing current (due to its extremely low resistance), Similarly, when electric current is passed into an, nichrome coil) becomes red-hot and produces heat. The cord of heater made of copper does not become red-hot or low because a negligible heat is produced in it on passing current (due to its extremely low resistance). The heating elements of most of the electric heating. Question 1. If due to some reason, a large current tends to flow through the electrical appliance, its fuse will blow up (melt and break), and cut off the electricity supply to the appliance. So, the filament-type electric bulbs are not power efficient (because they waste a lot of electricity as heat).The wastage of electricity can be reduced by using fluorescent tube lights and Compact Fluorescent lamps (CFLs) for producing light (in place of filament-type electric bulbs. The credit for the invention of the electric bulb is usually given to Thomas Alva Edison, though others before him had worked on it. When the fuse grip, carrying fuse wire is inserted in the fuse holder, then the. According to the heating effect of the electric current, a wire becomes hot as current is passed through it. Cause of heating effect of electric current: Electric current generates heat to overcome the resistance offered by the conductor through which it passes. When, a short circuit or overloading occurs, the fuse wire blows out cutting off the electricity supply. Question 9 Why nichrome wires are used in electrical appliances? Heating elements have high melting point so that they do not get damaged due to the heat generated. She has started this educational website with the mindset of spreading Free Education to everyone. A lot of heat is produced in the heating element because it is made of high resistance nichrome wire. Class 7 Heating Effects of Electric Current Class 7 Video | EduRev Summary and Exercise We have Provided Electric Current and Its Effects Class 7 Science MCQs Questions with Answers to help students understand the concept … Greater the magnitude of current passed through a given wire, greater will be the heat produced in it. Meaning of Heating Effect When an electric current passes through a conductor (like a high resistance wire) the conductor becomes hot after some time and produces heat This is called heating effect of Electric Current Example 1 A bulb becomes hot after its use for some time.This is because of heating effect of electric current Example 2 Different factors affect these benefits such as … Heating Effect of Electric Current. This is due to the conversion of some of the electrical energy that passes through the conductor, into heat energy. Before buying any electrical appliance, we should look for the ISI mark of the Bureau of Indian Standards on the appliance (ISI stands for Indian Standards Institution). The electric bulb (or electric lamp) which we use for producing light works on the heating effect of electric current. Draw the circuit diagram to represent the circuit shown in Fig. This large current may heat the wires to a dangerously high temperature and a fire may be started.We should never use such an electrical appliance having connecting cable with torn insulation. The glass tube has two metal caps at its two ends. Due to its high resistance, the heating effect of current will be much more in the fuse wire than anywhere else in the circuit. So they do not waste electricity by producing heat and hence they are very power efficient. as electric room heater, electric iron, electric kettle, electric toaster, electric oven, water heater (geyser), The electric heating appliances (such as electric room heater, electric iron, etc.) One insulated wire is called, The touching of live wire and neutral directly is known as, When the live wire and neutral wire touch each other directly, then. (1) Resistance of wire (This depends on material of wire , heat produced in it will be extremely small (due to which the copper wire will become negligibly hot). These days more and more houses and other buildings are using miniature circuit breakers to be replaced (MCBs) to protect the electric wiring from the excessive flow of current. Appliances which require heating effect have conductors or the heating elements. This video is highly rated by Class 7 students and has been viewed 1361 times. The part of electric heating appliance which ‘heats up’ on passing current is called heating element of the appliance. Some of the important applications of the heating effect of current are given below: (1) The heating effect of electric current is utilised in the working of electrical heating appliances such as electric room heater, electric iron, electric kettle, electric toaster, electric oven, water heater (geyser), immersion rod, and soldering iron, etc. Both these wires are necessary for the working of an electrical appliance. If, however, there were no fuse in the household wiring, then the large current flowing through the, ring could heat up the wires to very high temperatures and cause electric fires. want Heating Effects of Electric Current Class 7 Video | EduRev notes & Videos, you can search for the same too.