Bianchi type-III magnetized cosmological model when the field of gravitation is governed by either a perfect fluid or cosmic string is investigated in Rosen’s [1] bimetric theory of gravitation. To complete determinate solution, the condition, viz., A=(BC)ⁿ, where n is a constant, between the metric potentials is used. We have assumed different equations of state for cosmic string [2] for the complete solution of the model. Some physical and geometrical properties of the exhibited model are discussed and studied.

The exact solutions of the field equations with respect to hypersurface-homogeneous Universe filled with perfect fluid in the framework of $f (R, T)$ theory of gravity (Harko et al, \emph{Phys. Rev.} D 84, 024020 (2011)) is derived. The physical behaviour of the cosmological model is studied.

In this paper, we have studied the solutions of plane-symmetric Universe with variable $\omega$ in the presence and the absence of magnetic field of energy density $\rho B$. A special law of variation for Hubble’s parameterproposed by Bermann in {\it Nuovo Cimento} B 74, 182 (1983) has been utilized to solve the field equations. Some physical and kinematical properties of the models are also discussed.

In this paper, we have studied the anisotropic and homogeneous Bianchi type-VI$_0$ Universe filled with dark matter and holographic dark energy components in the framework of general relativity and Lyra’s geometry. The Einstein’s field equations have been solved exactly by taking the expansion scalar ($\theta$) in the model is proportional to the shear scalar ($\sigma$). Some physical and kinematical properties of the models are also discussed.

In this paper,we study themodel of $f (T )$ gravity in the presence of dark matter and modified holographic Ricci dark energy (MHRDE) in locally rotationally symmetric (LRS) Bianchi type-I space–time. To achieve a physically realistic solution of the field equations, we have considered volumetric power and exponential expansion laws. We plot the corresponding cosmological parameters for dark energy components in terms of redshift; thereafter we investigate the accelerated expansion of the Universe. The physical and geometrical parameters of the models are also discussed in detail. The Statefinder diagnostic pair and jerk parameter are analysed to characterise completely different phases of the Universe.

In the present paper, we investigated spherically symmetric space–time for bulk viscosity in the context of Brans–Dicke theory (BBT) of gravitation. It is observed that the Universe is accelerating for small values of expansion scalar and decelerating for large values of expansion scalar. The coefficient of bulk viscosity is negative, the wormhole is compact in Case I whereas in Case II, it is proportional to energy density and positive and the wormhole is non-compact. The required conditions for the wormhole are satisfied.