a) In the figure below with black on turn, black must move his king
into check and white wins in the next move.
In the following solution, both black and white will move to lose if they are on turn.
So if you capture (imprison) the king of your opponent, you may be possible to capture (take) it in the next move.
b) Yes, there is, see the figure below with black on turn. Blacks king
is checked, but the event of having no move for black occurs earlier
than the possibility for white to kick blacks king off the board.