Photo AI
12. A student carries out an investigation to determine the refractive index of a prism - Scottish Highers Physics - Question 12 - 2015
Question 12
12. A student carries out an investigation to determine the refractive index of a prism. A ray of monochromatic light passes through the prism as shown. The angle o... show full transcript
Worked Solution & Example Answer:12. A student carries out an investigation to determine the refractive index of a prism - Scottish Highers Physics - Question 12 - 2015
Step 1
Using the square-ruled paper on Page thirty-five, draw a graph of D against θ.
Answer
To create the graph of deviation (D) against angle of incidence (θ):
-
Set up the axes: The x-axis should represent the angle of incidence (θ) in degrees, and the y-axis should represent the angle of deviation (D) in degrees. It's best to start both axes at 0° and mark suitable intervals.
-
Plot the points: Plot the following points derived from the table:
- (30°, 47°)
- (47°, 40°)
- (40°, 38°)
- (60°, 32°) Ensure that each point is accurately represented on the graph.
-
Draw the curve: Connect the points with a smooth U-shaped curve, showing the relationship between θ and D.
Step 2
Step 3
Step 4
Use this relationship and your answer to (c) to determine the refractive index of the prism.
Answer
To find the refractive index n:
-
Determine A: Given that A (the angle at the top of the prism) is typically stated or measured. Assume A = 60° for this example.
-
Substitute values into the equation:
[ n = \frac{\sin(\frac{60°}{2})}{\sin(\frac{60° + 37°}{2})} ] [ n = \frac{\sin(30°)}{\sin(48.5°)} ] [ n = \frac{0.5}{\sin(48.5°)} \approx 1.02 ] The refractive index of the prism is approximately 1.02.
Step 5
Using the same apparatus, the student now wishes to determine more precisely the minimum angle of deviation.
Answer
To improve the precision in determining the minimum angle of deviation, the student should consider:
-
Taking more measurements: By extending the range of angles of incidence around the previous values and ensuring a more detailed read.
-
Minimizing errors: Use a more precise apparatus for measuring angles and ensure that the light source remains stable to obtain consistent readings.