An experiment was set up to determine the refractive index of a material - Leaving Cert Physics - Question 2 - 2016

On the diagram, the following measurements should be indicated:

1. Angle of incidence (i) - measured between the incoming ray and the normal at the interface.
2. Angle of refraction (r) - measured between the refracted ray and the normal.
3. Real depth - the depth of the object in the liquid.
4. Apparent depth - the depth as seen from the surface of the liquid.

These measurements are crucial for calculating the refractive index.

The instrument used to take these measurements is commonly a protractor or a ruler. A protractor is used to precisely measure the angles, while a ruler helps measure the depths accurately.

The refractive index (n) 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.
  Additionally, for the context of depth measurements, the refractive index can also be expressed as:
  $n = \frac{\text{real depth}}{\text{apparent depth}}$

Repeating the experiment is essential to ensure accuracy and reliability of the results. By conducting multiple trials, one can:

• Identify and reduce any experimental errors.
• Ensure consistency in measurements.
• Validate the results for reproducibility.
  Repeating the experiment helps establish a more definitive value for the refractive index.