Prism Viva Questions – Minimum Angle of Deviation Meth
Prism – Viva Questions
To determine angle of minimum deviation for a given prism by plotting a graph between angle of incidence and angle of deviation
A. Basic Understanding
Q1. What is a prism?
Answer: A prism is a transparent refracting medium with plane surfaces; therefore, it bends light by refraction.
Q2. What is the angle of a prism?
Answer: The angle between the two refracting faces is the prism angle; hence, it affects deviation.
Q3. What happens to light when it passes through a prism?
Answer: Light refracts at both faces; consequently, it deviates from its original path.
B. Conceptual Questions
Q4. What is the angle of deviation?
Answer: The angle between the incident ray and emergent ray is the angle of deviation; therefore, it measures bending.
Q5. What do you mean by minimum deviation?
Answer: Minimum deviation is the least value of deviation; thus, it occurs for a specific incidence.
Q6. Why does deviation change with angle of incidence?
Answer: Because refraction depends on incidence angle, deviation varies; hence, a curve forms.
C. Graph-Based Questions
Q7. Which graph do we plot in this experiment?
Answer: We plot angle of incidence against angle of deviation; therefore, we locate the minimum point.
Q8. What does the lowest point on the graph represent?
Answer: The lowest point represents minimum deviation; hence, it gives the required value.
Q9. Why is the graph symmetric about minimum deviation?
Answer: Because equal deviations occur for equal incidences on either side; therefore, symmetry appears.
D. Formula-Related Questions
Q10. Which formula connects refractive index and minimum deviation?
Answer: μ = sin((A + D)/2) / sin(A/2); therefore, refractive index can be calculated.
Q11. Which quantity remains constant for a given prism?
Answer: The prism angle remains constant; hence, material properties stay fixed.
E. Accuracy and Observation
Q12. Why are readings taken for different angles of incidence?
Answer: Multiple readings reveal the trend; therefore, minimum deviation is identified accurately.
Q13. Why does the graph method give better accuracy?
Answer: The graph reduces random errors; consequently, the result becomes reliable.
F. Errors and Precautions
Q14. What error occurs due to improper alignment?
Answer: Improper alignment changes deviation values; therefore, the graph shifts.
Q15. Why should parallax be avoided?
Answer: Parallax alters angle readings; hence, it causes measurement error.
G. Applications
Q16. Where do we use the principle of minimum deviation?
Answer: We use it in spectrometers; therefore, refractive index is measured.
Q17. Why do prisms disperse white light?
Answer: Because refractive index varies with wavelength, colors separate; consequently, dispersion occurs.
Final Understanding
Q18. What does this experiment help determine?
Answer: It determines the angle of minimum deviation; thus, it supports optical theory.
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