BTEC Applied Science - Physics Exam Questions. Explain 2 advantages of using digital signals instead of analogue signals to transmit television programmes. (2 marks) - ANSWER1. Digital Signals can carry more info than Analogue signals. 2. Less interference so better quality is produced. Give 2 other differences between visible light waves and sound waves. (2 marks) - ANSWER1. Visible light is electromagnetic whereas sound is a vibration 2. Sound waves has a lower frequency than visible ligh...