A certain band-limited signal has bandwidth \(B=20 \mathrm{kHz}\). Find the FFT size required so that the frequency resolution is \(\Delta f=50 \mathrm{~Hz}\). Assume radix \(2 \mathrm{FFT}\) and a record length of 1 second.

Assume that a certain sequence is determined by its FFT. If the record length is \(2 \mathrm{~ms}\) and the sampling frequency is \(f_{\mathrm{s}}=10 \mathrm{kHz}\), find \(\mathrm{N}\).