In this video, we will be discussing the Physical layer of OSI reference model in detail. 
The lowermost layer in Open System Interconnection (OSI) Model is Physical Layer. Physical Layer is the electrical as well as physical description of system. It includes several network components such as power plugs, connectors, receivers, cable types, etc. 

Physical Layer transmits data bits from one computer to another computer. Physical Layer defines encoding types i.e how the 0’s and 1’s are converted into signal. Physical Layer is allows communication of the unstructured raw data streams over a physical medium.

OSI model’s physical layer interconnect with signaling and hardware mechanism. Physical layer is responsible for physical connectivity of two different devices (computers). 

The services are provided by Physical layer to Data-link layer & in turn Data-link layer gives frames to physical layer. Physical layer converts them to electrical pulses, which represent binary data. Binary data is then transmitted over guided or unguided transmission media.

Functions performed by Physical layer:
1) Representation of Bits
2) Data Rate
3) Synchronization
4) Interface
5) Line Configuration
6) Transmission Modes

The Physical Layer is concerned with transmitting raw bits over a communication channel. The issue has to do with making sure that when one side sends 1 bit, it is received by the other side as 1 bit and not as 0 bit. The design issues here largely deal with mechanical, electrical & timing interfaces, and the physical transmission medium lies below the physical layer.

Physical layer in OSI model: https://www.geeksforgeeks.org/physical-layer-in-osi-model/