Now that I have heard that capacitors "allow" ac signals but "block"
dc signals as below.

Xc=1/[2(pi)(Fc)],

Fc=frequency of signal.

Now for dc signals Fc=0 Hz sothat Xc~infinity which implies that it is
open circuited,so we conclude that capacitor blocks dc signals and
allows ac signals(as they have a definite value of Fc).


But the problem is he Why do we use capacitors in radio circuits to
"block" noise signals which are nothing but ac signals?????

Can any one please explain where I am going wrong?????