Question 10
(a)(i) A transverse wave equation of a wave travelling in the x-direction with displacement y is expressed as y = A sin (wt + ф), where ф is the phase difference and the other symbols have their usual meaning. Show that the equation can be expressed as
(ii) A wave motion is expressed by the equation
Where x and y are in metres. Determine
(I) wavelength of the wave;
(II) frequency of the wave.
(b) State three applications of ultrasound.
(c)(i) Differentiate between harmonics and overtones.
Observation
Part (a) Candidates performance was below average.
Part (b) Performance was below average.
Part (c) Candidates performance was average.
The expected answers are:
(a) (i) The expression of the wave equation
(b) Applications of ultrasound: Used
- for measuring distance
- for detecting (invisible) flaws
- for imaging
- for scanning
- in cleaning of machine parts
- in cleaning of jewellery
- for oil exploration.
(c) (i) Differentiating between harmonics and overtones
Harmonics are notes of frequencies which are whole number multiples of the fundamental frequency while overtones are notes of frequencies higher than the fundamental frequency.
