Frequency Amplitude Wavelength Speed in air
I gave my students this multiple choice question: A person produces two sound waves with a flute, one immediately after the other. Both sound waves have the same pitch, but the second one is louder. Which of the following properties is greater for the second sound wave?

Only one answer is correct among these 4 choices:
- Frequency
- Amplitude
- Wavelength
- Speed in air

Could you tell me which one is correct?

Amplitude