Answer:
The number is [tex]N = 18[/tex]
Explanation:
From the question we are told that
The distance of separation is d = 4.5λ
Generally equation for nodal lines for two pint source is mathematically represented as
[tex]N = \frac{ 2 * m * d }{\lambda }[/tex]
Here m is 2 represented number of point source
[tex]N = \frac{ 2 * 2 * 4.5\lambda }{\lambda }[/tex]
=> [tex]N = \frac{ 2 * 2 * 4.5\lambda }{\lambda }[/tex]
=> [tex]N = 18[/tex]
