14 2-24.   Which of the following instruments is used to test the specific gravity of a lead- acid battery's electrolyte? 1.  Hydrometer 2.  Hygrometer 3.  Electrometer 4.  Gravitometer 2-25.   Smoking is prohibited in the vicinity of lead-acid storage batteries for which of the following reasons? 1.  Cigarette smoke neutralizes the electrolyte 2.  Lead-acid batteries produce explosive hydrogen when they are being charged 3.  Fumes produced by a lead-acid battery mixed with cigarette smoke produce a toxic by-product 4.  All of the above 2-26.   When testing dry cell batteries, which of the following procedures should you follow? 1.  The battery should be tested under load conditions 2.  The battery should not be tested under load conditions 3.  The battery should be tested at various temperatures 4.  Both 2 and 3 above 2-27.   Which of the following dry cell batteries is rechargeable? 1.  NICAD 2.  Alkaline 3.  Carbon-zinc 4.  Mercury cells 2-28.   Which of the following is the correct maximum charge rate for a NICAD battery rated at 300 milliampere hours? 1.  300 milliamperes for 15 hours 2.    60 milliamperes for 15 hours 3.    30 milliamperes for 15 hours 4.  600 milliamperes for 15 hours 2-29.   Which of the following is a characteristic of fixed rf attenuators? 1.  They are used to match impedances 2.  They are designed to handle small amounts of rf power 3.  They are usually built into the equipment in which they are used 4.  They are capable of handling several kilowatts of power 2-30.   Which of the following is an easy method of performing an operational test on a decade resistor? 1.  Use an swr meter 2.  Use the resistance substitution method 3.  Read the resistance with an ohmmeter 4.  Apply an rf voltage across the decade, measuring the voltage drop and computing the resistance 2-31.   Which of the following is/are the disadvantages of glass-core, fiber-optic cables? 1.  They are smaller in diameter than plastic-core fibers 2.  They are extremely susceptible to mechanical damage 3.  They exhibit signal losses as high as 25 dB/km 4.  Both 2 and 3 above 2-32.   Which of the following types of test equipment should you use to measure the losses in a fiber optic cable if only one end of the cable is accessible? 1.  An optical ohmmeter 2.  A Wheatstone bridge 3.  An optical power meter 4.  An optical time-domain reflectometer