Bad Qubits — Learn Quantum by Doing

|q⟩ Bad Qubits

Multiple choice

When you display either qubit of the Bell state

|\Phi+\rangle = (|00\rangle + |11\rangle)/\sqrt{2}

on its own Bloch sphere, where does its arrow point, per this lesson?

To the south pole, representing $|1\rangle$
To the origin (center), because the reduced state is maximally mixed ( $I/2$ )
To the $+x$ equator, the same as $|+\rangle$
To the north pole, since the joint state is pure