Sound waves: WAEC Physics Past Questions and Answers

What the WAEC syllabus covers in Sound waves

Our summary: How sound is made and travels, echoes, musical notes, vibrating strings and air columns, and resonance.

• Sources of sound
• Transmission of sound waves (Experiment to show that a material medium is required.)
• Speed of sound in solid, liquid and air (To be compared. Dependence of velocity of sound on temperature and pressure to be considered.)
• Echoes and reverberation (Use of echoes in mineral exploration, and determination of ocean depth. Thunder and multiple reflections in a large room as examples of reverberation.)
• Noise and music
• Characteristics of sound (Pitch, loudness and quality.)
• Vibration in strings (The use of sonometer to demonstrate the dependence of frequency ($f$) on length ($l$), tension ($T$) and mass per unit length (linear density) ($m$) of string should be treated. Use of the formula $f_0 = \frac{1}{2l}\sqrt{\frac{T}{m}}$ in solving simple numerical problems. Applications in stringed instruments: e.g. guitar, piano, harp and violin.)
• Forced vibration (Use of resonance boxes and sonometer to illustrate forced vibration.)
• Resonance, harmonics and overtones (Use of overtones to explain the quality of a musical note. Applications in percussion instruments: e.g. drum, bell, cymbals, xylophone.)
• Vibration of air in pipes - open and closed pipes (Measurement of velocity of sound in air or frequency of tuning fork using the resonance tube. Use of the relationship $v = f\lambda$ in solving numerical problems. End correction is expected to be mentioned. Applications in wind instruments e.g. organ, flute, trumpet, horn, clarinet and saxophone.)

Syllabus content © The West African Examinations Council (WASSCE (harmonised West African syllabus)).