Refraction Through Prism & Finding Angle of Deviation Experiment for i = 45 | Physics Demo STD 10

Summary

This video tutorial focuses on the practical aspects of using a glass prism in an experiment, addressing common queries and misconceptions. It explains that the angle of incidence is not equal to the angle of emergence in a prism, except in the special case of minimum deviation. The step-by-step demonstration includes setting up the experiment, measuring angles, and determining the angle of deviation. The tutorial emphasizes accuracy and allows for minor human errors, encouraging viewers to comment with any doubts. The video concludes with a thank you message for the support received.

Takeaways

• 🔬 The experiment involves using a glass prism to demonstrate the principles of light refraction and the angles involved, clarifying that the angle of incidence is not equal to the angle of emergence in a prism, unlike a glass slab.
• 📚 The script emphasizes the special case of 'minimum deviation' where the angles of incidence and emergence are equal, which only occurs when the prism is positioned in a specific way.
• 📏 The experiment requires marking and measuring angles accurately, using a protractor to determine the angle of incidence, which is set at 45 degrees in this demonstration.
• 📍 The setup includes an A4 size paper attached to a wooden board, with pins used to align and mark the paths of light rays.
• 📌 The experiment involves aligning pins to create a straight line with the images of the pins seen through the prism, ensuring the accuracy of the light path observation.
• 👀 It's important to view the experiment from the correct angle, with one eye closed and the eye parallel to the surface of the prism to observe the alignment of the pins' images.
• 📝 The script instructs on marking the locations where the pins are aligned with the images, which helps in tracing the path of the light rays.
• 📐 The angle of emergence is measured using a protractor, and it is found to be approximately 53 degrees in this experiment, differing from the angle of incidence.
• 📉 The angle of deviation is calculated by extending the incident and emergent rays and measuring the angle between them, which is approximately 38 degrees.
• 🔍 The refractive index can be determined using Snell's law and the measured angles of incidence and emergence.
• 📊 The experiment concludes with the suggestion to plot a graph of the angle of incidence versus the angle of deviation to find the minimum deviation and understand the relationship between these angles.

Q & A

What is the main purpose of repeating the prism experiment in the video?

The main purpose is to clarify the misconception that the angle of incidence is always equal to the angle of emergence when dealing with a glass prism, and to demonstrate the correct procedure for conducting the experiment.

Why is the angle of incidence not equal to the angle of emergence in a glass prism experiment?

The angle of incidence is not equal to the angle of emergence in a glass prism experiment because it only happens in a special case known as the minimum deviation case. This does not occur with a glass slab where the angles are generally equal.

What special case allows the angle of incidence to be equal to the angle of emergence in a prism?

The special case is known as the minimum deviation case. When the prism is positioned to achieve minimum deviation, the angle of incidence becomes equal to the angle of emergence.

How is the angle of incidence set in the experiment described in the script?

The angle of incidence is set by using a protractor to mark a 45-degree angle on the A4 size paper where the prism is placed.

What is the significance of marking the center of the A4 size paper with a dot?

Marking the center of the A4 size paper with a dot helps to accurately place the prism and ensures that the experiment is conducted symmetrically around the center point.

Why are two pins used in the experiment, and what is their purpose?

Two pins are used to create a reference for the angle of deviation. They are placed at a distance and their images are aligned to form a straight line, which helps in determining the path of the refracted and emergent rays.

What is the approximate distance between the two pins used in the experiment?

The approximate distance between the two pins is about 7 centimeters, as mentioned in the script.

How is the angle of emergence measured in the experiment?

The angle of emergence is measured by aligning a protractor with the emergent ray and the normal to the prism surface, then reading the angle formed.

What is the method to find the angle of deviation in the experiment?

The angle of deviation is found by extending the emergent and incident rays with dotted lines and measuring the angle formed between the extended lines using a protractor.

How can the refractive index be determined using the angles of incidence and emergence?

The refractive index can be determined using Snell's law, which relates the angle of incidence and the angle of refraction. By measuring these angles, one can calculate the refractive index of the prism material.

What is the significance of plotting a graph of the angle of incidence versus the angle of deviation?

Plotting a graph of the angle of incidence versus the angle of deviation helps to visualize the relationship between these angles and to identify the minimum deviation point, which is important for understanding the optical properties of the prism.