Answer
See graph.
Work Step by Step
Start from the graph of $y=\sqrt x$ (red), as $h(x)=\sqrt {4x}=2\sqrt x$, stretch vertically by a factor of $2$ to obtain $h(x)=\sqrt {4x}$ (purple).
Another way is to start from the graph of $y=\sqrt x$ (red), shrink horizontally by a factor of $4$ to obtain $h(x)=\sqrt {4x}$ (purple).
