An experiment was carried out to measure the refractive index of a substance - Leaving Cert Physics - Question 3 - 2008

During the experiment, the following measurements were taken:

1. Angle of Incidence (i): The angle at which the incident ray strikes the glass block.
2. Angle of Refraction (r): The angle at which the refracted ray exits the glass block.
3. Real Depth: The actual thickness of the glass block.
4. Apparent Depth: The depth of the substance as observed from the ray diagram.
5. Critical Angle: The angle at which total internal reflection occurs, if applicable.
6. Diagrams: Measurements may also be inferred from the diagram.

The refractive index (n) of the substance can be calculated using the formula:

$n = \frac{\sin(i)}{\sin(r)}$

where:

• i is the angle of incidence,
• r is the angle of refraction.

To find the apparent depth (d_apparent) and real depth (d_real):

$n = \frac{d_{real}}{d_{apparent}}$

By taking measurements of the angles and depths, the refractive index can be accurately calculated.

The experiment was repeated for several reasons:

1. Accuracy: To ensure the accuracy of the measurements.
2. Error Reduction: To minimize the impact of random errors in the measurements. Each repetition helps identify and correct faulty readings.
3. Consistency: To verify that results remain consistent across multiple trials, enhancing reliability.
4. Partial Assurances: It ensures that the derived refractive index is a robust result.