$.$ When the receiver is not available in the physical world, then the message cannot be sent to the receiver. There is a chance of misinterpretation of messages when the communication channel is wrong. The wrong communication channel can be a barrier to effective communication.

Justification of wrong communication channel as a communication barrier:

Justification of wrong communication channel as a communication barrier is given below:

The wrong communication channel is a communication barrier because the communication process is incomplete without a receiver. The communication process is one$-$way traffic when the receiver is not available. The message cannot be sent to the receiver if the receiver is not available in the physical world.

The wrong communication channel is a communication barrier because the message cannot be sent to the receiver if the receiver is not available in the physical world.

The wrong communication channel is a communication barrier because there is a chance of misinterpretation of messages when the communication channel is wrong. The receiver might interpret the message in a wrong way if the communication channel is wrong.

The wrong communication channel is a communication barrier because there is a chance of misinterpretation of messages when the communication channel is wrong.

Final answer: Examples of wrong communication channels are given below:

Sending a message through a postcard and sending a message through a telegram are examples of wrong communication channels.

Sending a message through a postcard and sending a message through a telegram are examples of wrong communication channels.

Hence, the wrong communication channel is a communication barrier.