In Young's double slit experiment, how many maxima can be seen on a screen (including central maxima) if \(d = \dfrac{5\lambda}{2}\) (where \(\lambda\) is wavelength of light and \(d\) is distance between the two slits).

The condition for maxima in Young's double slit experiment is given by \(d \sin \theta = n \lambda\), where \(n\) is an integer.

Given \(d = \dfrac{5\lambda}{2} = 2.5 \lambda\).

Substituting the value of \(d\) in the condition for maxima:

\(2.5 \lambda \sin \theta = n \lambda\)

\(\sin \theta = \dfrac{n}{2.5}\)

Since the maximum possible value of \(\sin \theta\) is \(1\), we have:

\(\left| \dfrac{n}{2.5} \right| \le 1\)

\(|n| \le 2.5\)

Since \(n\) must be an integer, the possible values of \(n\) are \(-2, -1, 0, 1, 2\).

Thus, there are \(5\) possible values for \(n\), which corresponds to \(5\) maxima on the screen (including the central maximum).

Answer: \(5\)