Muhammad YasirFA18-RMT-049LHR TP 6027Dr. Abdul Jawad2026-03-122020https://repository.cuilahore.edu.pk/handle/123456789/2718It is not for the sun to exceed the moon, nor does the night leave behind the day. They all float/travel, each in an orbit. (Quran 36:40) The Joule-Thomson effect and quasinormal modes (QNMs) onto regular non-minimal magnetic black hole (BH) with a cosmological constant are being investigated. For this purpose, we extract some thermodynamical parameters such as pressure P and mass M in the presence of magnetic Qm as well as electric q charge. These parameters lead to inversion tem perature Ti, pressure Pi and corresponding isenthalpic curves. Introducing the tortoise coordinate, however, the Klein-Gordon wave equation leads to the second-order ordinary Schr¨odinger equation. For this BH, computing complex frequencies of QNMs under the scalar field perturbation satisfied their boundary conditions by using the Wentzel-Kramers-Brillouin (WKB) technique. Moreover, we consider the Lorentz symmetry violating Ba˜nados, Teitelboim and Zanelli (BTZ) BH and Hairy BH of dimensionally contin ued gravity. These solutions are obtained in massive gravity and power Yang-Mills magnetic field. We utilize the general form of first law of BH thermodynamics and compute different thermodynamical quantities. The cosmological constant Λ (either positive or negative) plays an important role in BH thermodynamics when treated as a positive thermodynamical pressure. We derive corresponding equations of state and discuss the phase transitions which is comparable with chemical Van der Waals fluid. We also find out the critical points and observe that system exhibits first order small as well as large BHs phase transitionenDr. Abdul JawadFA18Department of MathematicsMathematicsBlack HolesThermodynamicQuantities and Quasinormal ModesThesis