As Shown Below, a Garden Room Has Three Walls, a Floor

Multiple Choice

As shown below, a garden room has three walls, a floor and a roof, but is open to the garden on one side. The wall widths are L and w. The roof height is h. When travelling sound waves enter the room, standing sound waves can be present in the room if the wavelength of the standing waves is:

A) $\frac{2 L}{n}$ , where n is a positive integer.
B) $\frac{4 w}{n}$ , where n is an odd integer.
C) $\frac{h}{n}$ , where n is an even integer.
D) in all cases listed above.
E) given by (a) or (b) above, but not by (c) .