Which of the following frequencies is classified as ultrasound?
18 Hz18\text{ Hz}18 Hz
1.8 kHz1.8\text{ kHz}1.8 kHz
18 kHz18\text{ kHz}18 kHz
28 kHz28\text{ kHz}28 kHz
Practise Edexcel GCSE Physics Sound, ultrasound and infrasound with exam-style questions for Foundation and Higher tier. 50 questions, matched to the Edexcel GCSE Physics (1PH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.