Step 1: Understanding the Concept:
Flip-flops are bistable devices with two complementary outputs, $Q$ and $Q'$. The state of the flip-flop is defined by the value of $Q$.
Step 2: Detailed Explanation:
- When $Q = 1$ (and consequently $Q' = 0$), the flip-flop is in the Set state.
- When $Q = 0$ (and consequently $Q' = 1$), the flip-flop is in the Reset (or Clear) state.
In the given condition, $Q = 0$, which corresponds to the Reset state.
Step 3: Final Answer:
The state is Reset.