What is the frequency of DC Voltage?

If we talk about pulsating or AC signals then it means some value of frequency but for DC it is 0 hz because the pulsating DC is when passed through filter it becomes pure DC and here we are talking about pure DC.. So its ZERO.

DC voltage frequency is always zero.

In AC we have different magnitude at different places , but if we will go for DC there is no change in magnitude, so that there will be no matter of cycle, so the value of frequency is zero.