“…Let G be a finite group of order n with identity element e. Chakrabarty et al [7] defined the undirected power graph P(G) of a group G as an undirected graph with vertex set as G and two vertices x, y ∈ G are adjacent if and only if one is the positive power of other, that is, x i = y or y j = x, for positive integers i, j with 2 ≤ i, j ≤ n. For some recent work on power graphs, we refer to [1,5,7,8,15] and the references therein. The adjacency spectrum, the Laplacian and the signless Laplacian spectrum of power graphs of finite cyclic and dihedral groups has been investigated in [3,6,11,16,20]. (n i + 1), so the order of the graph…”