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 of the following is not true about LED? While connecting to a circuit, the longer lead of LED is always connected to the positive terminal of the battery. While connecting to a circuit, the shorter lead of LED is always connected to the positive terminal of the battery. There are two wires (called leads) attached to an LED. LED can be used to detect weak current. None 2. 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 3. In charging a battery of motor car, which of the following effect of electric current is used? heating induction chemical magnetic None 4. What happens when you join the free ends of the tester for more than a few minutes? There would be no conduction of electricity. Cells of the battery will drain quickly. All of the above The current will not be able to pass None 5. The process of depositing a layer of gold on silver is known as: Silver plating Electrolysis None of these Electroplating None 6. 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 7. Of the following, the one that does not make use of chemical effect of electric current is : Electroplating Electrotyping Voltaic cells Thermoelectric refrigerator None 8. In charging a battery of motor-car, which of the following effect of electric current is used? Heating Magnetic Chemical Induction None 9. Which of the following metals is used in electroplating to make objects appear shining? chromium iron copper aluminium None 10. 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. BothUse of LED in tester. andA tester using magnetic effects of current. Use of LED in tester. None 11. The process in which a layer of one metal is coated with another metal by electrolysis is called: Electrostatics Electropathy Electrorefining Electroplating None 12. 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 Thomson William Nicholson William Harvey William Watson None 13. 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 (ii) is correct (iii) is correct (iv) is correct (i) is correct None 14. In electroplating of the silver spoon with gold, the silver spoon is cleaned with a dilute acid solution to remove the _________ from its surface. silver layer oxide layer gold layer chloride layer None 15. An electric current can produce heating effect only. chemical, heating, and magnetic effects. magnetic effect only. chemical effect only. 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.
