How many nodal lines are created by two point sources emitting at the same wavelength λλ that are separated by a distance equal to 4.5λ4.5λ? Express your answer as an integer.

The number is  

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

Here  m  is  2  represented number of point source

=>  

=>  

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.