Question

In a fixed medium (that means constant physical properties) which one of the following is not true?

	Doubling the frequency (f) of a waves causes wavelength (λ) to double.
	The speed of sound waves in air is higher at higher temperatures.
	The speed of waves that the medium allows to propagate is a constant.
	Higher (f) or frequency waves must therefore have shorter (λ) or wavelength.

Answer 1

1. Frequency is given by: ​​​​​​ Hence f is inversely proportional to wavelength. Therefore doubling frequency causes wavelength to reduce to half.(Answer)
2. Molecules at higher temperatures have more energy, thus they can vibrate faster. Since the molecules vibrate faster, sound waves can travel more quickly. Hence speed of sound increases with temperature.
3. Speed of sound is constant for a given medium.
4. As state already, higher frequency leads to shorter wavelength.

ANSWER:A.