A student investigated the interference of sound waves - Edexcel - A-Level Physics - Question 2 - 2023 - Paper 3

A potential health and safety issue is the loud sound levels, which could damage the student's hearing. This can be mitigated by wearing ear protection, such as ear defenders or plugs, or by limiting the duration of exposure to loud sounds.

To calculate the separation $w$ of the maxima, subtract the distances of adjacent maxima measurements.

Using the data: Total distance from A to B is $3.33 ext{ m}$ and first maximum is at $0.22 ext{ m}$, thus, the calculated distance is $3.33 - 0.22 = 3.11 ext{ m}$. The number of gaps between the maxima is $5$. Therefore, the value of $w$ is given by: $w = \frac{3.11}{5} = 0.62 ext{ m}$.

To find the wavelength $ho$, we use the formula: $\lambda = \frac{w s}{D}$ Given:

• $w = 0.62 ext{ m}$
• $s = 0.11 ext{ m}$
• $D = 4.0 ext{ m}$, we substitute these values into the equation: $\lambda = \frac{0.62 \times 0.11}{4.0} = 0.0170 ext{ m} = 17 ext{ cm}.$

At the point equidistant from the loudspeakers, destructive interference can occur if the sound waves from both speakers are out of phase. This results in a minimum intensity even if the distance from the speakers appears equal.

To determine the speed of sound, the student would need a timing device, such as a stopwatch, to measure the time it takes for the sound to travel a known distance. Additionally, a distance measuring tool, like a measuring tape, would be necessary to measure the distance accurately.

If the speed of sound increases, the separation $w$ will also increase, assuming that $D$ remains constant and that the conditions of the investigation do not change. This is expressed in the relationship: $w = \frac{D}{s}.$ Thus, with higher speed, the value of $w$ will increase as long as $D$ and $s$ remain constant.