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Computational work and experimental results of interest in plasma spectroscopy are presented in this thesis which is in two parts. In the first part, two computer programs are described. These are for calculating the composition of plasmas in Saha equilibrium and equilibrium parameters behind incident and reflected strong shock waves. These programs are then used to predict the state of the reflected shock in a helium-filled electromagnetic T-tube. Observations on the HeI 5876 Å line showed that the plasma produced could not be considered as truly shock heated, but an interesting result emerged from these observations. This was the behavior of electron density versus filling pressure curve which showed a maximum similar to that observed in a Z-pinch. This effect is explained in terms of shock theory. The first part of the thesis ends with a description of the measurement of the shift-to-width ratio of the He I 5876 Å line. The second part of the thesis begins with a review of the modern theory of electron impact broadening of spectral lines. After that, measurements of the shift-to-width ratio of the AII 4806 Å line and the shift of the AII 3351 Å line over the temperature range 25,000°k to 45,000°k are described. These lines were radiated by the plasma from an argon-filled Z-pinch. Detailed computational work was performed to investigate the distortion of line profiles and errors in temperature measurements caused by plasma inhomogeneity. Host of the diagnostic work described in this thesis was performed by observations on spectral lines i.e. use was made of the effect of different plasma parameters on line profiles.