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. 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 2. An electric current can produce chemical, heating, and magnetic effects. heating effect only. magnetic effect only. chemical effect only. None 3. In electroplating of a silver spoon with gold, the gold plate is connected to: None of these Both positive and negative terminals of the battery The positive terminal of the battery The negative terminal of the battery None 4. Which of the following devices can be used to detect a weak current? A tester using magnetic effects of current. Use of electric bulb in tester. Use of LED in tester. BothUse of LED in tester. andA tester using magnetic effects of current. None 5. In charging a battery of motor-car, which of the following effect of electric current is used? Magnetic Heating Chemical Induction None 6. 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. There would be no conduction of electricity. The current will not be able to pass None 7. The process in which a layer of one metal is coated with another metal by electrolysis is called: Electrostatics Electropathy Electrorefining Electroplating None 8. The process of depositing a layer of gold on silver is known as: Electrolysis None of these Silver plating Electroplating None 9. 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 Watson William Thomson William Harvey None 10. Which of the following is not true about LED? 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. LED can be used to detect weak current. None 11. Which of the following metals is used in electroplating to make objects appear shining? chromium iron aluminium copper None 12. In LEDs, the longer lead is connected to ................ and the shorter lead is connected to ................... Negative terminal, Positive terminal Positive terminal, Neutral terminal Negative terminal, Neutral terminal Positive terminal, Negative terminal None 13. Of the following, the one that does not make use of chemical effect of electric current is : Electrotyping Electroplating Thermoelectric refrigerator Voltaic cells None 14. In charging a battery of motor car, which of the following effect of electric current is used? induction heating magnetic chemical None 15. 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 (i) is correct (ii) is correct (iii) is correct (iv) is correct 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.
