Answer
The distance between the central bright band and the bright band on either side of the central band is $~~0.48~cm$
Work Step by Step
Let $\Delta y$ be the distance between each dark band and the successive dark band.
Note that $\Delta y$ is also the distance between each bright band and the successive bright band.
We can find $\Delta y$:
$(3+0.5)~\Delta y = 1.68~cm$
$\Delta y = \frac{1.68~cm}{3.5}$
$\Delta y = 0.48~cm$
Therefore, the distance between the central bright band and the bright band on either side of the central band is $~~0.48~cm$
