Time-Frequency resolution explained 

Sampling rate (in the time domain) is how many samples are being acquired in a given time. In this video, I considered two cases wherein the signal was being acquired with different sampling rates (2500Hz and 25000Hz). Now sampling rate has a consequence in the frequency domain which is bandwidth. One has to sample the signal at least 2.5 times than the highest frequency of interest. Hence in acoustic recordings, as our frequencies of interest lies within the human hearing range (20Hz - 20KHz), we usually sample at 48KHz. In other words a signal sampled at 48KHz would result in a bandwidth of up to 20KHz in the frequency domain. If the signal was only sampled at 24KHz then the bandwidth is now reduced to around 12KHz because the current sampling frequency is too slow to accurately sample the fast oscillating high frequency waves. To answer the other question: If your sine wave of 5Hz is sampled at 10Hz and 100Hz, the bandwidth in frequency domain is different in each case although you will only see 5Hz result in the spectrum. If you had an additional sine wave of say 20Hz then you cannot sample it with 10Hz as it is less than 20Hz, it will fail to capture it.