Four statements related to deriving the relationship between wave speed, wavelength and frequency are listed below, but they are not in a logical order.
P. Speed is defined as distance travelled divided by the time taken.
Q. In one time period T, a wave travels a distance equal to one wavelength λ.
R. Frequency f is the reciprocal of the time period.
S. Substituting the value of T in the speed expression gives the required relation.
(i) Arrange the statements P, Q, R and S in the correct logical order needed to arrive at the relation between v,λ and f.
(ii) Using the arranged statements, write the complete derivation that leads to the expression v=λf.
(iii) State one basic assumption about the medium that is implicitly made in this derivation.