Which layer uses the physical media to send packets?

• A. The data link layer
• B. The physical layer
• C. The network layer
• D. The application layer

Answer: (B)

The main idea is that the physical layer is responsible for carrying data over the actual transmission medium. It defines how raw electrical, optical, or radio signals are generated, modulated, timed, and interpreted so bits can travel across copper, fiber, or air. In practice, the physical layer takes the bitstream from the layer above and converts it into signals that travel through the medium, handling voltage levels, timing, and connectors. The data link layer above it deals with framing, MAC addressing, and error detection, while the network layer handles routing and logical addressing, and the application layer deals with software-facing protocols. So even if the term “packets” is used in the question, the function of using the physical medium to send the signal belongs to the physical layer.