B- A 7 km optical link consists of multimode step index fiber with a core refractive index of 1.5 and a relative refractive index difference of 1%. Estimate: (a) the delay difference between the slowest and fastest modes at the fiber output; (b) the rms pulse broadening due to intermodal dispersion on the link; (c) the maximum bit rate that may be obtained without substantial errors on the link assuming only intermodal dispersion; (d) the bandwidth-length product corresponding to (c).