A student records pairs of values of the speed of sound v and the absolute temperature T of air and plots v against T. The plotted points lie close to a straight line.
a. (i) Explain qualitatively why a graph of v versus T for a given gas is expected to be a straight line.
b. (ii) State what physical constant(s), if any, can be extracted from the gradient of such a line and justify your answer.
c. (iii) Two of the data points are (T=273K,v=331ms−1) and (T=313K,v=355ms−1). Using only these two points, estimate the numerical value of the gradient dTdv and interpret its physical meaning.