The diagram shows a waveform - Leaving Cert Physics - Question 7 - 2010

Frequency is defined as the number of complete wave cycles that pass a given point in one second, measured in Hertz (Hz). It represents how often the wave oscillates.

Natural frequency refers to the frequency at which an object tends to oscillate when not subjected to a continuous external force. It is determined by the physical characteristics of that object, such as its mass and stiffness.

To calculate the wavelength (λ), we use the formula:

$λ = \frac{c}{f}$

where:

• c = speed of sound (340 m/s)
• f = frequency (250 Hz)

Substituting the values:

$λ = \frac{340 \, m/s}{250 \, Hz} = 1.36 \, m$

(c) The loudness of a sound is primarily dependent on the amplitude of the wave; a larger amplitude results in a louder sound.

(d) The pitch of a sound depends on the frequency of the wave; higher frequency results in a higher pitch.

An opera singer can shatter a glass when singing a high-pitched note because of resonance. If the frequency of the note matches the natural frequency of the glass, the vibrations from the sound waves can cause the glass to oscillate with increasing amplitude until it ultimately breaks.

To demonstrate resonance, one can use the following procedure:

1. Apparatus: Use a tuning fork and an adjustable length of air column (a resonant tube).
2. Procedure: Strike the tuning fork to produce sound and position it near the opening of the resonant tube filled with water. Adjust the water level until you find the length of air column at which the sound is amplified.
3. Conclusion: You will notice that the sound becomes louder at certain lengths, indicating resonance between the tuning fork and the air column. This phenomenon occurs when the frequency of the tuning fork matches the natural frequency of the air column, amplifying the sound.