Ncert – class 8- science – Chapter 11: Chemical Effects of Electric Current 2 Welcome to your Ncert - class 8- science - Chapter 11: Chemical Effects of Electric Current 2 1. Which one of the following scientists showed that if electrodes are immersed in water and a current was passed, bubbles of oxygen and hydrogen were produced? William Nicholson William Harvey William Thomson William Watson None 2. The process of depositing a layer of gold on silver is known as: Electrolysis None of these Electroplating Silver plating None 3. What happens when you join the free ends of the tester for more than a few minutes? All of the above Cells of the battery will drain quickly. The current will not be able to pass There would be no conduction of electricity. None 4. A tester is used to check the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows brightly for liquid A while it glows very dimly for liquid B. You would conclude that(i) liquid A is a better conductor than liquid B.(ii) liquid B is a better conductor than liquid A.(iii) both liquids are equally conducting.(iv) conducting properties of liquid cannot be compared in this manner (iii) is correct (i) is correct (iv) is correct (ii) is correct None 5. Which of the following is not true about LED? LED can be used to detect weak current. There are two wires (called leads) attached to an LED. While connecting to a circuit, the shorter lead of LED is always connected to the positive terminal of the battery. While connecting to a circuit, the longer lead of LED is always connected to the positive terminal of the battery. None 6. An electric current can produce magnetic effect only. heating effect only. chemical effect only. chemical, heating, and magnetic effects. None 7. In charging a battery of motor-car, which of the following effect of electric current is used? Chemical Heating Magnetic Induction None 8. In electroplating of a silver spoon with gold, the gold plate is connected to: Both positive and negative terminals of the battery The positive terminal of the battery The negative terminal of the battery None of these None 9. The process in which a layer of one metal is coated with another metal by electrolysis is called: Electrorefining Electropathy Electroplating Electrostatics None 10. In electroplating of the silver spoon with gold, the silver spoon is cleaned with a dilute acid solution to remove the _________ from its surface. oxide layer gold layer chloride layer silver layer None 11. Of the following, the one that does not make use of chemical effect of electric current is : Thermoelectric refrigerator Electrotyping Voltaic cells Electroplating None 12. Which of the following metals is used in electroplating to make objects appear shining? iron copper chromium aluminium None 13. In charging a battery of motor car, which of the following effect of electric current is used? chemical magnetic heating induction None 14. Which of the following devices can be used to detect a weak current? Use of LED in tester. Use of electric bulb in tester. A tester using magnetic effects of current. BothUse of LED in tester. andA tester using magnetic effects of current. None 15. In LEDs, the longer lead is connected to ................ and the shorter lead is connected to ................... Negative terminal, Positive terminal Positive terminal, Negative terminal Negative terminal, Neutral terminal Positive terminal, Neutral terminal None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to commentEnter your email address to commentEnter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
