For ten points, name this interval between the notes C and G.
Two flutes, separated by this interval, play together throughout the second movement of Bartók's Concerto for Orchestra. In a perfect authentic cadence, the bass voice descends by this interval to the final chord. This interval separates the first two notes of the Nature motif that opens the "Sunrise" section of Also Sprach Zarathustra. A major key that is this interval above another major key will have either one less flat or one more sharp than it, thus continuously ascending by this interval produces the "circle of" this interval. The strings of a violin are tuned apart by this interval, the ratio of the first and second overtones. This is the interval between the tonic and dominant, and the inversion of this interval is the perfect fourth. For ten points, name this interval between the notes C and G.
Two flutes, separated by this interval, play together throughout the second movement of Bartók's Concerto for Orchestra.
perfect {fifth} (do not accept diminished fifth or augmented fifth)