Find the refractive index of a transparent liquid using a hollow prism by measuring the prism angle and minimum deviation, with procedure and viva questions.
Objective:
To find the refractive index of a transparent liquid using a hollow glass prism.
Procedure
Firstly, fill the hollow prism with the liquid whose refractive index you need to find.
Next, place the prism on the spectrometer table and adjust it carefully.
Then, observe the reflected rays from both sides to find the angle of the prism.
After that, rotate the telescope slowly until you get the minimum deviation position.
Finally, calculate the refractive index using this formula:
n=sin(A+D2)sin(A2)n = \frac{\sin\left(\frac{A + D}{2}\right)}{\sin\left(\frac{A}{2}\right)}
Here, A is the prism angle, and D is the minimum deviation.
Therefore, the refractive index of the given liquid is accurately determined.
Viva Voce
Q1. What is the function of a collimator in a spectrometer?
Ans: It produces parallel rays of light.
Q2. What is the angle of minimum deviation?
Ans: It is the smallest angle between the incident and emergent rays when light passes symmetrically through the prism.
Q3. What are the main parts of a spectrometer?
Ans: The spectrometer has three main parts:
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Collimator
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Prism table
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Telescope