Final answer:
A student can calculate the refractive index of glass using a multistep experiment with a glass block, by applying Snell's Law to measure angles of incidence and refraction, comparing these values to known indices, and observing the total internal reflection to find the critical angle.
Step-by-step explanation:
To find an accurate value for the refractive index of glass, a student can use a glass block and perform a refraction experiment. This involves multiple steps:
First, measure the angle of incidence and the angle of refraction for light entering the plastic from air. As the index of refraction of air is approximately known (1.0003), using Snell's Law, which states that n1*sin(θ₁) = n2*sin(θ₂), the student can calculate the index of refraction of the plastic.
Next, measure the angle of incidence and the angle of refraction for the light as it passes from the plastic into the hollow space filled with gas. The index of refraction of the plastic is known, so again applying Snell's Law, the student can deduce the index of refraction of the gas.
To understand how light speed varies in different materials, one can list materials based on their refractive index. The lower the refractive index, the faster the speed of light in the medium. Therefore, ordering air (1.0003), water (1.333), and glass (1.52) from fastest to slowest would be: air, water, and then glass.
Finally, for more accurate results, the student could attempt to observe the phenomenon of total internal reflection within the plastic block. By adjusting the angle of incidence and aiming to make the refracted ray disappear, one can measure the critical angle. This measured angle can then be compared with the prediction from Snell's Law to verify the calculated indices of refraction.
These methods together help students understand how light behaves as it moves through different media and thereby measure the indices of refraction for various materials.