Add a few drops of lemon juice or dilute hydrochloric acid to distilled water in one cap. This chapter will strengthen your base for future complex topics. Question 13. Chromium is used for electroplating because it has a shiny appearance, does not corrode and is scratch resistant. Solution: (c) Sodium chloride You will also love the ad-free experience on Meritnation’s Living Science 2019 Solutions. Question 3. The seawater contains a huge amount of salts in comparison to drinking water, hence the seawater is a better conductor of electricity and it produces a stronger magnetic field in the wire and hence deflects the compass needle more. Water is dissociated into its constituent gases, i.e., hydrogen and oxygen. Take the tray from inside a discarded matchbox. Can you ex¬plain the reason? Answer: Wrap an electric wire a few times around the tray. Answer: Answer: Question 11. Wrap copper wires around the metal caps of the carbon rods and join them to a battery (Fig. The free copper gets drawn to the plate connected to the negative terminal of the battery and gets deposited on that plate. Attach the free ends of the wires to a LED. Question 18. What are insulators ? Take two pieces of copper wire and iron wire. It cannot be said for sure that liquid does not conduct electricity because : Question 2. Now, check the Class 8 Science Chapter 14 question answer PDF on the main website of Vedantu. Iron is a strong metal used for making bridges. Question 21. Give the construction of LED. Answer: Class 8 NCERT exercise wise questions and answers will help students frame a perfect solution in the Maths Exam. Question 1. Record your observations in Table 14.1. To her surprise she found that the compass needle showed deflection. A child staying in a coastal region test the drinking water and also the seawater with his tester. Place a small compass needle inside it. What is LED? Compact Fluorescent Lamps. Air is an insulator of electricity. In Chapter 8 of Grade 8 Science, we have to study about few synthetic fibres like Nylon, Rayon or Artificial Silk, Polyester and Acrylic.We should know about the properties of these synthetic fibres. The free copper gets deposited on the plate acting as cathode. (c) Sodium Answer: Explain why they do this. Give some uses of LED. Answer: In Class 8 Science Chapter 3, the descriptions of man-made fires and their uses are given. If not, what can we do to make it conducting ? Clean their metal caps with sand paper. Noise pollution, its causes, impacts, and control measures are explained towards the finish off the chapter. Answer: Answer: Question 5. Students of class 8 will be writing national level exams … You may also get distilled water from a medical store or a doctor or a nurse). Question 3. (b), Question 8. When People Rebel Class 8 Extra Questions and Answers Social Science History Chapter 5 CBSE Pdf free download are part of Extra Questions for Class 8 Social Science.Here we have given NCERT Extra Questions for Class 8 Social Science SST History Chapter 5 When People Rebel. (a) Sea water If it is still not working then replace the cells with fresh cells. On passing electric current through the conducting solution of lemon juice and water, chemical reaction takes place. Question 2. The process of depositing a layer of any desired metal on another material by means of electricity is called …………. Distilled water does not have any salts dissolved in it, but rain water may have some impurities in it. Chapter 3: Synthetic Fibres and Plastics. NCERT Solutions for Class 6, 7, 8, 9, 10, 11 and 12. Answer: (ii) liquid B is a better conductor than liquid A. Vedantu is a platform that provides free NCERT Solution and other study materials for students. [NCERT]. LEDs require very little energy and glow even if a small current is passing through the circuit. (c) cathode Which properties of chromium make it useful for electroplating on iron ? So, the compass needle showed deflection. Question 4. What is the objective of electroplating ? When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Answer: Dip the ends of the wire in the given liquid. The filament of the bulb is heated due to current and then it glows. Chromium has a good shine, it resists scratches and is corrosion resistant. Explain. Question 12. Activity 7 (NCERT Textbook, Page 177) Now connect one free end of the wire to the terminal of a battery. So, the deflection of the compass needle is more. Question 10. (d) photodiode Do you find any difference in any one of them? He finds that the compass needle deflects more in the case of seawater. What is electrolysis ? Therefore, it becomes thin. 14.6. The disposal of the used conducting solution after electroplating is hazardous and can cause environmental pollution. Class 8 Science Chapter 14 MCQ with Answers 1. Question 6. Does lemon juice or vinegar conduct electricity? Answer: Materials which do not allow electric current to flow through them are called insulators. Sound talks about the distinction between music and noise. [NCT 2011] Can you think of the possible reasons? Revise concepts such as synthetic fibres and types of synthetic fibres … (i) The wires in the circuit may be loosely connected. Class 8 Science Chapter 13 Sound. Answer: Most liquids that conduct electricity are solutions of …………, ………. Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? We prefer not to do electroplating on iron used for bridges because it is very costly. (b) solids only. Question 2. In this activity, if the bulb does not glow, it means that either the connections of the circuit are loose or the bulb is fused or cells are used up. Answer: Question 19. (a) conduction Answer: But when salt is dissolved in distilled water and again tested, the bulb glows which shows that water containing salts conduct electricity. The bulb does not glow in the setup shown in Fig. Yes, the solution does conduct electricity. Place them in fresh lemon fruit. as a point source of light in laser beam torches. Take out carbon rods carefully from two discarded cells. Copper from impure rod is sought to be transferred to the thin copper plate. Answer: Answer: LED glows showing the flow of current. Answer: Materials which do not allow electric current to flow through them are called insulators. Can we do electroplating on it to protect is from corrosion ? The articles to be plated should be cleaned throughly to remove dust, grease or any deposit on it. If the ends of the wire of tester are touched for a long time, the cells will be finished very soon. Vedantu is a platform that provides free, and other study materials for students. Answer: What is electroplating? If the current in the circuit is small, how can we test its presence ? If the ends of the wire of tester are touched for a long time, what will happen ? Here we Provide Class 6 Science Question Answer, Important Questions, MCQ for Various State Boards Students like CBSE, Haryana, uttar pradesh, mp and other state students. Now remove the electrodes from the solution and look at them carefully. Question 6. Question 2. 14.5. may cause the magnetic needle to deflect. What are insulators or poor conductors? The liquid is a conductor and the circuit is also complete, but the bulb does not glow. Take another piece of wire and connect it to the other terminal of the battery (Fig. What are electrodes ? What could be the reasons? Question 13. Vinegar, lemon juice and tap water. (ii) The bulb may be fused. Thus food, stored in iron cans, is prevented from being spoilt due to iron by electroplating it by tin. Apart from chemical effect, which other effect electric current produce ? Answer: Jake three clean plastic or rubber caps of bottles. Answer: Answer: By volume of hydrogen gas is twice the volume of oxygen gas. Changes of colour of solutions may occur depending on what solution and electrodes are used. (d) Potassium synthetic fibres and plastics class 8 notes. Question 14. (d) sides of the container Now dissolve a pinch of common salt in distilled water. Question 10. [NCERT] Answer: The substances that […] Answer: (d) Vinegar Thus, lemon juice, vinegar, tap water, milk, curd and water, and soda are good conductors of electricity while vegetable oil, honey, kerosene oil, and distilled water are poor conductors of electricity or insulators. A metal is released in the electrolysis of a salt. Join the free ends of two wires momentarily. Can you explain the reason ? Bridges and automobiles are prevented from rusting by plating them with zinc. Use plating artificial jewellery with gold. This solution for Class 8 Science Chapter 8 has answers to all the questions present in Chapter 8. Why is chromium used for electroplating ? The Class 8 Science Chapter 14 Solutions are now made easy to understand all the concepts and topics related to the chapter precisely. All Living Science 2019 Solutions for class Class 8 Science are prepared by experts and are 100% accurate. Class 8 is one of the crucial stages of a student’s life. Paheli had heard that rainwater is as good as distilled water. These questions will test your cognizance, understanding, evaluating and mathematical skills. Battery with which this electrode is connected worries of acing the exams refer! Converge white light are used as electrodes dissolved salts called conductors the students if... 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