An electric buzzer is suspended inside four different sealed glass jars. From which jar will an observer outside not hear the sound of the buzzer?
a sealed jar filled with nitrogen gas
a sealed jar filled with helium gas
a sealed jar with a vacuum inside
a sealed jar filled with water
295 exam-style questions on CIE IGCSE Physics Sound, covering Sound. Each one has a worked solution and a mark scheme showing where the marks go.