Which of the following statement is true regarding Bohr's model of hydrogen atom ? (I) Orbiting speed of electrons decreases as if falls to discrete orbits away from the nuclues. (II) Radii of allowed orbits of electrons are proportional to the principle quantum number. (III) Frequency with which electrons orbit around the nucleus in discrete orbits is inversely proportional to the principle quantum number. (IV) Binding froce with which the elctron is bound to the nuclues increases as it shifts to outer orbits. Selected the correct answer using the codes given below:
