Cisco Networking Academy Program CCNA 1 and 2 Companion Guide, Revised part 22 is the Cisco approved textbook to use alongside version of the Cisco Networking Academy Program CCNA 1 and CCNA 2 web-based courses. The topics covered provide you with the necessary knowledge to begin your preparation for the CCNA certification exam (640-801, or 640-821 and 640-811) and to enter the field of network administration. | I Page 179 Tuesday May 20 2003 2 53 PM Check Your Understanding 13. Which fiber-optic cable type is typically used for outside installations A. Tight-buffered B. Tight-tube C. Loose-buffered D. Loose-tube 14. What is the light source typically used in single mode fiber optics A. Photo transistor B. Laser C. Photo resistor D. LED 15. Which term describes the angle at which a ray hits a glass surface A. Angle of reflection B. Angle of refraction C. Angle of incidence D. Angle of attack 16. Modulation is a process of changing amplitude frequency or phase. Which acronym does not represent a type of modulation A. AM B. FM C. PM D. RM 17. Which range does not correctly identify an unlicensed wireless frequency A. GHz B. 5 GHz C. 9 GHz D. 900 MHz 18. Which statement does not describe a benefit of spread spectrum A. Spread-spectrum transmissions are transmitted at high speeds. B. Spread spectrum is less susceptible to radio noise. C. Spread spectrum has a higher probability of correct reception. D. Spread spectrum creates little interference. Page 180 Tuesday May 20 2003 2 53 PM 180 Chapter 3 Networking Media 19. Which statement does not describe the features of direct-sequence spread spectrum DSSS A. DSSS is reliable because each bit is represented by a string of 1s and 0s. B. If up to 40 percent of the string is lost the original transmission can be reconstructed. C. DSSS technology has low throughput of data and short-range access. D. The recently released evolution of the IEEE standard provides for a full Ethernet-like data rate of 11 Mbps over DSSS. 20. Which of the following is not a feature of wired equivalent privacy WEP A. WEP uses the RC4 stream cipher for encryption. B. WEP is a security mechanism defined within in the standards. C. One of the goals of WEP is to deny access to the network by unauthorized users who do not possess the appropriate WEP key. D. None of the above. Page 181 Tuesday May 20 2003 2 53 .
