AM-Amplitude ModulationWhen there is a modulation in the amplitude of any sound wave then its called amplitude modulation.These signals are generally used for long distances.FMFrequency ModulationWhen there is modulation in the frequency of sound wave. It is called frequency modulation.It is generally used for short distances.Use of Silence- 1. Silence improves the quality of the whole conversation. 2. Silence always provides a relaxation to the listener. 3. Silence helps us to understand the radio production clearly. 4. Without silence the meaning of number of sentences changes when not used with proper gaps and pauses. 5. Silence improves the aesthetic values of the radio production. 6. But silence should be used in a controlled manner; otherwise it will be dad air.Sound and its relation to picture- 1. Sound always adds aesthetic value to any picture. 2. Sound clearifies any image or picture. 3. Sound improves the message of any picture or image. 4. Sound hooks up the target group and adds the artistic sence to any image.