en عمومى General پژوهشي Research paper <div style="text-align: justify;">In the present investigation, we study the reflection of plane waves, that is, Longitudinal displacement wave(P-Wave), Thermal wave(T-Wave) and Mass Diffusive wave(MD-Wave) in thermodiffusion elastic-half medium which is subjected to impedence boundary condition in context of one relaxatioon time theory given by Lord and Shulman theory (L-S) and the Coupled theory (C-T) of thermoelasticity. The expressions of amplitude ratios are obtained numerically and their variation with angle of incidence is presented graphically for a particular model to emphasize on the impact of impedence parameter, relaxation time and diffusion. Some special cases are also deduced.</div> Thermodiffusion, Amplitude Ratios, Plane waves, Impedence boundary. 1 17 http://ijmsi.ir/browse.php?a_code=A-10-3721-1&slc_lang=en&sid=1 S. Kaushal sachin_kuk@yahoo.co.in 10031947532846009682 10031947532846009682 Yes Department of Mathematics, School of Chemical Engineering and Physical Sciences, Lovely Professional University, Punjab, India K. Parmar kulmaths@gmail.com 10031947532846009683 10031947532846009683 No Department of Mathematics, IKG Punjab Technical University Hoshiarpur Campus, Punjab, India Priya 10031947532846009684 10031947532846009684 No Department of Mathematics, School of Chemical Engineering and Physical Sciences, Langara College Vancouver, British Columbia, Canada