Question

Q.1.What happens when a parallel beam of light is passed through a hypo-solution and is focused on screen ?.
2.when a few drops of sulphuric acid is added and then focused?

Answer 1

1. the image of the same color is formed on the screen. for eg: if a torch giving a yellow colored ray is used then a yellow dot will appear on the screen as no scattering takes place in the solution.
2. when sulphuric acid is added to the solution sulphur particles are given out into the solution and the ray of light is scattered such that the bright red color dot is observed on the screen this shows that the other wavelengths of light have been scattered.

Answer 2

Hypo solution is Sodium thiosulfate solution in water.. Na2S2O3.  It is a transparent solution.  It has refractive index like glass:   1.489.


When Sulfuric acid is added then Sulfur, SO2, Water, Na2 SO4 (Sodium sulphate ) are formed.  Sulfur particles are visible in the solution. They are opaque.  The Sodium sulfate solution has a refractive index of 1.394.

Q1)  Hypo solution acts like a convex lens and forms a real inverted image. 

Q2) Sulfur particles reflect and scatter light rays.  However, Sodium sulfate also acts as convex lens but of less refractive index.
      Thus a real image is formed a little more distance away. There will be dots also in the image. These are shadows of Sulfur particles.