In this paper, we present the monotonicity properties of the ratio between generalized elliptic integral of the first kind K a (r ) and its approximation log[1 + 2/(ar )], and also the convexity (concavity) of their difference for a ∈ (0, 1/2]. As an application, we give new bounds for generalized Grötzsch ring function μ a (r ) and a upper bound for K a (r ).