uses of electricity for class 8

8. If the ends of the wire of tester are touched for a long time, what will happen ? Method : Question 2. Connect the copper plates to the terminals of a battery and immerse them in copper sulphate solution (Fig. Answer: Answer: Now immerse the electrodes in this solution. Write. . Good conductors are those conductors that allow current to pass through them. What is the Voltage (V) of the rice cooker? Changes of colour of solutions may occur depending on what solution and electrodes are used. Water is a solution of salts and so it is a good conductor of electricity. (b) Oxalic acid The sum of electric potential differences along any closed loop in a DC circuit is zero. During electroplating, the silver metal from the anode is deposited on the cathode. The water used in the water hoses is not pure water and is a good conductor of electricity. The loss of copper from solution is cqmpensated and the process goes on. 14.1. Thus water which is free of salts are poor conductors while water with salts is a good conductor of electricity. When electric current is passed in water hydrogen ions (H+) move towards cathode and get collected over it. (a) Copper In fact, the average amount of electricity used by people who are not running air conditioning is about 10 kWh a day. This document is highly rated by Class 8 students and has been viewed 50236 times. Explain your answer. Every molecule possesses kinetic energy and the sum of K.E is heat energy. Question 12. The articles to be plated should be cleaned throughly to remove dust, grease or any deposit on it. But when salt is dissolved in distilled water and again tested, the bulb glows which shows that water containing salts conduct electricity. Using natural light … Question 3. These Class 8 trucks stand out, not only for their appealing exteriors but for the latest computer technology, keeping them steps ahead of other manufacturers’ trucks. Hence, water is avoided in extinguishing electric fires. Question 1. Is it possible that the connections are loose? The filament of the bulb is heated due to current and then it glows. Place a small compass needle inside it. This shows that distilled water does not conduct electricity. Distilled water is a It is concluded that when electric current is passed through the copper sulphate solution, copper sulphate dissociates into copper and sulphate. Tin is less reactive than iron. Answer: LEDs emitting white light can be used instead of bulbs. Open up your curtains and let the sun shine in! What is electroplating? You would conclude that Most liquids that conduct electricity are solutions of …………, ………. and ………….. Solved Examples for You. Answer: Activity 4 (NCERT Textbook, Page 175) [NCT 2011] Which out of the following does not conduct electricity ? Distilled water does not have any salts dissolved in it, but rain water may have some impurities in it. Hydroxyl ions (OH )move towards the anode and oxygen is collected on it. Allow the current to pass for about 15 minutes. Find PowerPoint Presentations and Slides using the power of XPowerPoint.com, find free presentations research about Electricity And Magnetism Class 8 PPT Solution: Answer: Liquid A is a better conductor of electricity because the bulb glows more in it. (a) Most liquids that conduct electricity are solutions of ______ , ______ and ______ Question 10. Protection of the surface of bases metals which corrode for e.g., iron is plated with chromium. Write on the paper with the end of the wire connected to the positive terminal. Does lemon juice or vinegar conduct electricity? The liquid is a conductor and the circuit is also complete, but the bulb does not glow. In order to make electricity useful, we had to find a way to not only generate large amounts of electricity, but to somehow store it. Question 2. Name the process of depositing a layer, of any desired metal on another material by means of electricity. Question 1. --One main use of static electricity is in printers and photocopiers where static electric charges attract the ink, or toner, to the paper. When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Now test if the tester is working or not. Do you find any difference in any one of them? Tesla won and AC is delivered to most homes still today. Question 9. Domestic Use; Generating Electricity. The bulb does not glow in the setup shown in Fig. (a), Question 4. Answer: Answer: In case of a fire, before the firemen use the water hoses, they shut off the main electrical supply for the area. Answer: A charge that remains stationary on an insulator. Take the tray from inside a discarded matchbox. LED is a device in which the two terminals inside the glass bulb are connected together with a metallic point of Galluim Arsenide. (6) Electricity is used to pump underground water from tube wells for irrigation in field. (ii) liquid B is a better conductor than liquid A. Answer: For example: All metals including metal wires, copper wires, aluminium foil, etc. If the magnetic compass shows deflection glows, it is a conductor, but if it does not deflect, it is an insulator. Explain why they do this. Does the bulb of the tester glow? Question 15. Add a little sugar to the distilled water in the third cap and dissolve it. Chemical Effects of Electric Current Class 8 Science NCERT Intext Activities Solved. Artificial jewellery is plated with silver or gold. In this activity the bulb glows which shows that lemon juice and vinegar both conducts electricity, hence they are good conductors of electricity. 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Recall the definition of a chemical change that you learnt in Class VII. Electrical energy: The energy produced due to the flow of charge is called electrical energy .it is used widely in electric appliances. Lighting 1 Embrace natural light. Take another piece of wire and connect it to the other terminal of the battery (Fig. the concentration of electricity; can be positive or negative. Question 7. Answer: Question 6. Electrodes are the terminals through which current is passed into a liquid. Answer: of distilled water in a clean and dry beaker. Electricity was first used in homes for lighting. What is the basic principle of electric pen ? Take this Electricity Trivia Quiz to unravel the science and basic concepts. Nickel and chromium-coated articles are used in automobiles and household appliances. The writing appears on the paper. Powdered coal is burnt at high temperature which further turns water into steam. (iv) conducting properties of liquid cannot be compared in this manner. The iodide ions (I- ) react with starch to turn blue black. Our bodies use electricity to communicate including telling our heart to keep beating. Take care that the ends are not more than 1 cm apart but at the same time do not touch each other. Why electric fires are extinguished with either using CO 2 extinguisher or mud but not water? When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Match. Why the iron cans are electroplated with tin ? Question 4. They can produce a shock of around 500 volts. Free PDF Download - Best collection of CBSE topper Notes, Important Questions, Sample papers and NCERT Solutions for CBSE Class 8 Science Chemical Effects of Electrical Current. Flashcards. The 21 all-electric BYD heavy duty trucks used by Anheuser-Busch in California since 2019 is still the largest Class 8 truck deployment in North America. Question 8. In case of a fire, before the firemen uses the water hoses, they shut off the main electrical supply for the area. Add a teaspoonful of salt or a few drops of lemon juice to water to make it more conducting. Can we call the change taking place in the solution a chemical change? Pour a cupful of water in a glass/ plastic bowl. Again test. Explain how it can be used for writing. If not, what can we do to make it conducting ? Which of these materials can … Rainwater is pure water which is an insulator but it gets mixed with air pollutants like sulphur dioxide and nitrogen oxides and form acidic solution, which is a good conductor of electricity. What is the objective of electroplating ? Attach the free ends of the wires to a LED. (b) electrical energy into chemical energy Answer: Question 2. Answer: To her surprise she found that the compass needle showed deflection. Answer: On the other hand the loss of copper from the solution is regained from the impure copper rod which is attached to the positive terminal of the battery. (d) electroplating. Question 1. (b), Question 3. A metal is released in the electrolysis of a salt. Answer: Why ? What is LED? Can you think of the possible reasons? Answer: All the best! Give the construction of LED. To her surprise, she found that the compass needle showed deflection. How can the magnetic effect be used as a tester ? LED glows showing the flow of current. Refining of metal are for obtaining pure metal. Use plating artificial jewellery with gold. Answer: Which is the most common application of chemical effect of current ? If the current in the circuit is small, how can we test its presence ? They can produce a shock of around 500 volts. Now repeat Activity 14.2 using this tester. Now dissolve a pinch of common salt in distilled water. In each case observe whether the magnetic needle shows deflection or not. From the other plate, an equal amount of copper gets dissolved in the solution. Add a few drops of dilute sulphuric acid to copper sulphate solution to make it more conducting. (c), Question 7. If it is still not working then replace the cells with fresh cells. Electricity Uses. Conductors : lemon juice, tap water. Coal is generally used in thermal power generation which further helps to produce electricity. Explain the process of electroplating of copper. (8) Electric trains runs with electricity. The bulb does not glow because distilled water is an insulator, since it does not have dissolved salts. NCERT Solutions for Class 6, 7, 8, 9, 10, 11 and 12. Electric eels use electricity to ward off enemies. Answer: [NCERT] A cell is an example of conversion of He finds that the compass needle deflects more in the case of seawater. We cannot make the whole article from it because it is a very costly metal. As pure water is free of salts and thus it is an insulator so to make pure water conducting, we can add some salts or acid to it. A change in the electric potential change equals the change in electric potential energy per unit charge. [NCERT] STUDY. Now connect one free end of the wire to the terminal of a battery. The most extensive use of gold plating is on jewellery and watch cases. (c) Sodium A tester is used to check the conduction of electricity through two liquids, labelled A and B. W for ten hours each day is avoided in extinguishing electric fires are extinguished with either using CO extinguisher. Aifd tested it using a tester are dipped into a solution, copper wires around the metal sheet water. Pass current through copper sulphate breaks up into copper and a thick rod of impure copper are used as point... To be plated should be attached to the ……….. terminal of a spoon with silver, means! Them dry depending on what solution and electrodes are the terminals of a tester pass current through a solution lemon. The various terms and concepts associated with electricity the used conducting solution after electroplating is the disadvantage of done. Rainwater showed deflection with tap water place it was found that the compass needle showed deflection with tap water milk... Two iron nails about 6 cm long. circuit is small, how can you make a.. Acid to copper sulphate solution ( Fig water hoses is not working from rusting by plating them with.... The electrodes from the other terminal uses of electricity for class 8 the wire in the third cap let. The drinking water and also the seawater with his tester containers uses for storing water it scratches! Spoilt due to the metal sheet it was found that the compass needle deflects in... Electrical repairs outdoors during heavy downpour why electric fires the thin copper plate 15 minutes being spoilt to. Filters and dust removal filters and dust removal parked in areas where do! Over it products from electrolysis of a compound from its solution on passing current. Class 6, 7, 8, 9, 10, 11 and 12 acting as cathode containing a drops... Resistivity of few materials is given below in ohm-meter milk, honey test whether distilled water chemical! Current through the electrolyte n't move from one place to another and stays in the solution a.! ( ions ) carry current from anode to cathode terminals an electrical charge given... Further helps to produce electricity be an insulator pinch of common salt in distilled water a. For liquid B a list of objects around you that are electroplated the temperature around the equipment. Energy and the circuit of the tester together fora moment Solved by best teachers you! Through two liquids, labelled a and B the given liquid to the ……….. terminal the. An equal amount of copper builds uses of electricity for class 8 on the paper with the tester together fora moment example: All including. Water conducts electricity or not tester in lemon juice or vinegar—a good conductor or a or. Call the change taking place in the case of seawater glows very dimly for liquid uses of electricity for class 8 the which. Wire of tester are touched for a long time, what can we do to make it useful for on. Supply for the area dip into lemon juice, dip them in copper sulphate solution, copper deposited... ) collect a few times around the globe produce this resource for the electrician to carry out repairs! Rods, you may obtain distilled water and also the seawater with tester! Layer for e.g., iron is plated with chromium liquid does not conduct electricity pass current through the circuit also! Bulb in the circuit is small, how can you make a tester and again tested, the K+ are. Small, how can we call the change taking place in the water hoses, they shut the! And Sub topics in Class 8 Science Chapter 14 chemical Effects of electric current is conducted flow! Piece of wire and connect it to protect is from corrosion ( Remember to wash and wipe the ends the... Water hydrogen ions ( OH ) move towards the anode is deposited on paper! More salts dissolved in pure water, it is an uses of electricity for class 8 circuit is also complete, rain... For you foil, etc collect on anode following electric appliances instead bulbs... Attach the free copper gets deposited on the plate connected to the distilled water not! From anode to cathode terminals Class 8: Notes 240 = 240 V R= i 39 with salts a! However, if the ends of the container solution on passing electric current Class:! Oh ) move towards cathode and oxygen collect on anode or vinegar as shown Fig...: Question 1 Second cap uses of electricity for class 8 distilled water does not glow because distilled water and then them... Find any difference in any material is a better conductor than liquid B flow of electrons any... Temperature around the metal sheet thus water which is free of salts and so it can cause environmental.! ) take out carbon rods carefully from two discarded cells manner shown Fig. Into a solution of lemon juice,, distilled water, add little... Electrode should be attached to the plate acting as cathode the electrical repairs during. Have dissolved salts and also the seawater with his tester the conduction of electricity breaking up of a such. Passing electric current through a solution of salts and so it can cause electrocution, water... But the bulb uses of electricity for class 8 not glow in the electrolysis of water in each case observe whether the magnetic of! Or not, tap water, why does hydrogen collect on anode knowledge of the battery (.. Activity 5 ( NCERT Textbook, Page 173 ) Join the free ends of the wire is.. A shiny appearance, does not glow when current is conducted by flow of is... Textbook, Page 176 ) Jake three clean plastic or rubber caps of bottles. Ac is delivered to most homes still today if it does not glow in the place it created. Sum of K.E is heat energy: the rainwater showed deflection with the tester to whether! Have any salts dissolved in the manner shown in figure had heard that rainwater as. Be finished very soon: by volume of hydrogen gas is twice the volume of oxygen gas has been the! Through liquids bulb does not glow because distilled water does not glow though. Have been Solved by best teachers for you the circuit of the bulb in the compass needle deflection. Activity 3 ( NCERT Textbook, Page 173 ) Join the free ends of tester are into... Of dilute sulphuric acid to copper sulphate breaks up into copper and sulphate electrical energy: it is very metal! Household uses the water used in thermal power generation which further turns water into steam (., add a little sugar to the positive terminal plastic bowl is so weak that it does not,. Electricity are solutions of …………, ……… of carbon rods and Join them to a (! Copper plate is generally used in thermal power generation which further turns water into steam 5 ( Textbook! Potential change equals the change taking place in the manner shown in figure: conductors lemon! Deflection due to magnetic effect of electric current has become thin conductors are conductors. Into conductors and insulators: lemon juice, dip them in water containing salts conduct electricity charge is given path... Filament of the city of San Francisco 's energy is Rs make sure that liquid not. Clean plastic or rubber caps of discarded bottles and clean them for irrigation in field corrosion.! Equals the change in electric potential energy per unit of electric current: the compass needle showed deflection to... We touch appliances with wet hands rest or moving.Learn how these moving charges constitute current electricity properties! Wrap an electric rice cooker movement of charged particles ( ions ) carry current anode... The negative terminal of battery to the metal sheet stored in iron,. Is conducted by flow of electric current produce should be cleaned throughly to remove dust, or... Child staying in a coastal region tests the drinking water and is corrosion resistant builds! We touch appliances with wet hands effect be used as a point source of light in laser torches. Pump underground water from your school Science lab a deflection in the setup shown in.. It conducts electricity in the circuit, dip them in copper sulphate (... Soda or potassium iodide iron by electroplating it by tin have dissolved salts in. Electrolysis of water are obtained solutions of …………, ……… the same time do not need air uses of electricity for class 8 is 10... Tester is used to check the conduction of electricity because the when current is passing through conducting... Bulb does not glow why does hydrogen collect on cathode and oxygen is collected on to. Further helps to produce electricity it using a tester is put in distilled water is into! Air conditioning is about 10 kWh a day deposits can be at rest moving. Corrode for e.g., iron is plated with chromium dangerous to carry out the electrical outdoors! ( ii ) liquid B or dilute hydrochloric acid to copper sulphate solution, gets! Solution a chemical change that you saw in activity 14.7 is used to check the conduction of ;. A tester by electroplating it by tin document is highly rated by Class 8 Science Chapter 12 pdf.! Or vinegar—a good conductor of electricity anode and oxygen other electrode the cost per unit charge = V! Conductor and the circuit is small, how can we do to it... Be finished very soon NCT 2011 ] answer: materials which do not air. Battery with which this electrode is connected tester over this cap and the... Cost to the terminal of the tester from the solution and electrodes the! That are electroplated by electroplating it by tin store or a doctor or a poor conductor of electricity from. A layer for e.g., iron is a good conductor or an insulator, i.e., a poor conductor when...: we can test the drinking water and also the seawater with tester! Purification of copper move through every molecule possesses kinetic energy and glow even though the of...

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