Iram AshrafCIIT/SP20-RMT-022/LHRDr. Shamaila RaniLHR TP 76522026-05-062021https://repository.cuilahore.edu.pk/123456789/3872In this thesis, we use some squared speed of sound models in the frame- work of the non-zero torsion theory for flat FRW spacetime. These squared speed of sound models depend on equation of state parameter. We dis- cuss the accelerated expansion of the universe through some cosmological parameters like Hubble parameter, deceleration parameter and statefinder parameters. For deceleration parameter, we get some constraints to be fulfilled by model parameters for the sake of accelerated expansion of the universe. The statefinder parameters show the ΛCDM limit as well as some consistent behavior for each model. We also check the validity of general- ized second law of thermodynamics and thermal equilibrium for each model by taking into account Bekenstein entropy. In terms of equation of state parameter having range of quintessence, cosmological constant as well as phantom era, we get some consistent results for particular values of model constants.enDepartment of MathematicsSP20Mathematicscosmologynon-zero torsionsquared speed of soundmodified gravityDr. Shamaila RaniThesis