MODULE 3 CHAPTER 5 QUIZ 4

Question Number. 31. The Daniel Cell electrodes are. Option A. copper and zinc. Option B. carbon and zinc. Option C. zinc and manganese dioxide. Correct Answer is. copper and zinc. Explanation. The Daniel Cell was an improvement on the first ever cell made by Voltaire. Both used copper and zinc electrodes ..................................

Question Number. 32. In a thermocouple, where is voltage measured?. Option A. At both junctions. Option B. At the hot junction. Option C. At the cold junction. Correct Answer is. At the cold junction. Explanation. The voltmeter measures the voltmeter across the cold junction of a thermocouple ..................................

Question Number. 33. Mercury cells are covered with a metal cover. Option A. as a protective cover. Option B. as a negative terminal. Option C. as a positive terminal. Correct Answer is. as a positive terminal. Explanation. The outer cover (or case) of a mercury cell is the positive terminal - Have a look at your watch or calculator battery to verify ..................................

Question Number. 34. The capacity of a battery is measured in. Option A. volts. Option B. ampere-hours. Option C. cubic centimetres. Correct Answer is. ampere-hours. Explanation. Battery capacity is in amperehours ..................................

Question Number. 35. A battery's internal resistance is determined by (OCV = Open Circuit Voltage, CCV = Closed Circuit Voltage). Option A. IR = (OCV – CCV)/ i. Option B. IR = (OCV + CCV) / i. ... Option C. IR = (OCV - CCV) / V. Correct Answer is. IR = (OCV – CCV)/ i. Explanation. Internal resistance (IR) has no effect on output voltage when Open Circuit. So Open Circuit Voltage (ocv) is higher than Closed Circuit Voltage (ccv). Using ohm's law (R=V/I), IR = (ocv) - ccv) all divided by current ..................................

Question Number. 36. There are more negative than positive plates in a lead acid battery because. Option A. it is necessary for chemical action to take place. Option B. it reduces the internal resistance of the cell. Option C. the positive plates are prone to warping if the chemical action is taking place only on one side. Correct Answer is. the positive plates are prone to warping if the chemical action is taking place only on one side. Explanation. A lead acid battery normally has one more negative plate than positive plate because the positive plates are prone to warping if the chemical action is taking place only on one side ..................................

Question Number. 37. What is the approximate internal resistance of a Leclanche cell?. Option A. 0.02 ohms - 4 ohms. Option B. 6 ohms - 10 ohms. Option C. 20 ohms - 30 ohms. Correct Answer is. 0.02 ohms - 4 ohms. Explanation. A leclanche cell is just another name for the zinc-carbon cell. Its IR is more like 0.4 - 4 ohms. Some good info on the types of cells and their IRs at External website… 

Question Number. 38. An aircraft battery on charge from the aircraft generators causes. Option A. battery voltage to increases to nominal voltage and the charge current decreases. Option B. internal resistance of the battery to decrease in sympathy with the decreasing charging current. Option C. battery voltage to decrease to zero until it is fully charged. Correct Answer is. battery voltage to decrease to zero until it is fully charged. Explanation. As the battery voltage increases, the current charging it decreases ..................................

Question Number. 39. What effect does hydrogen have in a battery cell?. Option A. Sulphation. Option B. Nothing. Option C. Polarization. Correct Answer is. Polarization. Explanation. Hydrogen, if allowed to form on the anode, reduces the battery output. This is polarization. ... Question Number. 40. To generate electricity with a fuel cell, you need a constant supply of. Option A. Nitrogen & Sunlight. Option B. Oxygen & Hydrogen. Option C. Kerosene & Heat. Correct Answer is. Oxygen & Hydrogen.