If you sample a cosine of fundamental period 0.1 milliseconds with a sampling rate of 10^5 samples per second, how much phase difference is there between two consecutive samples?
I can't solve this problem and can't seem to find it's answer anywhere.
The cosine needs 0.1 milliseconds $=10^{-4}$ seconds for a phase difference of $2\pi$, so $\Delta \phi/\Delta t=2\pi\times 10^4$ Hz. Sampling is at $10^5$ Hz or $10^{-5}$ seconds per sample, $\Delta t=10^{-5}$ s. So $\Delta \phi = (\Delta \phi/\Delta t) \times \Delta t=2\pi 10^4\times 10^{-5}=\pi/5$.