Answer
$3.65\times10^{-34}J \cdot s$
Work Step by Step
The magnitude of the angular momentum depends only on $\mathcal{l}$.
$$L=\sqrt{\mathcal{l}(\mathcal{l}+1)}\hbar=\sqrt{12}\hbar$$
$$=\sqrt{12}\hbar=\sqrt{12}(1.055\times10^{-34}J \cdot s )$$
$$=3.65\times10^{-34}J \cdot s $$
