Suppose that the channel’s outgoing end is in the hydrogen $\mathcal{l}\mathbf{=}\mathbf{0}$Stem-Gerlach apparatus of the figure. You place a second such apparatus whose channel is aligned with the first but rotated $\mathbf{90}\mathbf{°}$about the $\mathit{x}$-axis, so that its B –field lines point roughly in the $\mathit{y}$-direction instead of the. What would you see emerging at the end of your added apparatus? Consider the behavior of the spin-up and spin-down beams separately. Assume that when these beams are separated in the first apparatus, we can choose to block one or the other for study, but also assume that neither deviates too far from the center of the channel.

The Stern-Gerlach experiment provides the demonstration for the quantization of the spatial orientation of the angular momentum, in this experiment a silver atom is used which is made to go through a spatially varying magnetic field.

In the experiment, each atom is not in a specific dipole up or down until it passes through the magnet that will measure its state with equal probability. Once the state is filtered, either it is dipole upstate or dipole downstate, not in a single left state.

So, when the beam is passed through the second apparatus. It is divided into two beams, depending on whether the second measuring process results in measuring a left-pointing or right-pointing spin.

Conclusion: Therefore, The one that emerges at the end of the added apparatus will be a beam with either a left-pointing or right-pointing spin.