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a. modal dispersion b. attenuation c. Both A and B about equally. 3-87 Businesses can select multimode fiber to transmit 1000BASE-SX signals farther by- a. buying fiber with lower modal bandwidth b buying fiber with wider core diameter c. Both A and B d. Neither A nor B 3-88 is a major propagation problem in optical fiber. Noise a. . Both A and B d. Neither A nor B 3-89. Wireless transmission usually is expressed in terms of a. frequency b. wavelength c. Both a. and b. 5-90 directions antennas transmit about equally strongly in all b. c. d. Dish Both A and B Neither A nor B 5-91 antennas transmit about equally strongly in all directions a. Adaptive b. Dish C. Radio d. Wideband 3-92. Which of the following offers more reliable transmission UTP b. Radio transmission. c. Both A and B have about equally reliable transmission characteristics. 3-93 Which of the following has faster attenuation with distance? UTP b. Radio transmission. c. Both A and B have about equally fast attenuation. 3-94. If the signal strength from an omnidirectional radio source is 8 milliwatts at 30 meters, how strong will it be at 90 meters? a. 64 mW b. 8/3 mW C. mW e. None of the above c. 1 mW d. 8/9 mW e. None of the above 3-95. When radio waves cannot pass through a large or dense object, this creates a. refractive interference b. a shadow zone c. multipath interference d. spread spectrum propagation effects e. Both A and B behind the object. 3-96. Ifa wireless transmitter and receiver are in the same room, walls can create between the two stations. a. shadow zones. b. multipath interference c inverse distance law attenuation even if they do not come directly inverse square law attenuation e EMI 3-97. In WLANs, the most serious propagation effect is a. atenuation b. EMI multipath interference d. shadow zones 3-98. In WLANs, EMI may be produced by a. devices in nearby WLANs b. microwave ovens c. Both A and B d. Neither A nor B 3-99. EMI increases with frequency b False 3-100. Absorptive attenuation increases with frequeney a. True b. False. 3-101 Which of the following increases with frequeney? a. EMI b. Multipath interference c. Both A and B d. Neither A nor B 3-102 Which of the following increases with frequency? a. Absorptive attenuation. b. EMI c. Both A and B d. Neither A nor B