Concept:Standard ethernet defines several physical layer implementations, Four are: 10 Base 5, 10 Base 2, 10 Base T, 10 Base F. All implementations use digital signaling at 10 Mbps.Explanation:10 Base 5 : This is for thick ethernet. It uses bus topology with an external transceiver. The maximum length must not exceed 500m.10 Base 2: it is used for thin ethernet. It also uses bus topology. The length of each segment can not exceed 185 m due to a high level of attenuation.10 Base T : It is for twisted pair ethernet. It uses a physical star topology. Maximum length of the twisted cable is 100 m.10 Base -F: it is several types of optical fiber 10 Mbps ethernet. It uses star topology. Maximum length of the cable is 2000 m and it uses manchester line encoding.