ASSOCIAÇÃO DE ESPELHOS PLANOS: O que é, Número de Imagens Formadas e Exemplos | Aula de Física Enem

Summary

This video explains the fascinating concept of how flat mirrors interact when placed at different angles, forming multiple images. It covers the formula used to calculate the number of images based on the angle between two mirrors, with a focus on how this changes when the angle is even or odd. The lesson also demonstrates the infinite reflections created by parallel mirrors and provides a practical example with two mirrors set at a 90° angle, resulting in three images. A clear and engaging introduction to the relationship between mirror angles and image formation.

Takeaways

• 😀 Two flat mirrors placed at an angle create multiple images of an object.
• 😀 The number of images formed by the mirrors can be calculated using the formula: N = (360 / α) - 1, where α is the angle between the mirrors.
• 😀 When the result of 360 divided by the angle (α) is an even number, the object can be placed anywhere, and multiple images will form.
• 😀 If the result of 360 divided by the angle (α) is an odd number, the object must be placed along the bisector of the angle between the two mirrors for images to appear.
• 😀 When two flat mirrors are placed parallel to each other, infinite images are formed due to continuous reflections.
• 😀 In a scenario where the angle between two mirrors is 90 degrees, three images will be projected, as calculated by the formula.
• 😀 The angle between the mirrors (α) significantly impacts the number of images formed, with smaller angles leading to more images.
• 😀 For parallel mirrors facing each other, the object is reflected back and forth between them, leading to an infinite number of images.
• 😀 The class explains the relationship between mirror angles and image formation, highlighting the geometric principles of light reflection.
• 😀 Understanding the behavior of images formed by flat mirrors is a fundamental concept in optics, particularly in studying light and reflections.

Q & A

What happens when two flat mirrors meet at a 90-degree angle?

When two flat mirrors meet at a 90-degree angle, multiple images of an object are formed. The number of images can be calculated using the formula: 360 ÷ α - 1, where α is the angle between the mirrors. For a 90-degree angle, three images will be formed.

How do you calculate the number of images formed by two mirrors?

The number of images formed by two mirrors can be calculated using the formula: N = (360 ÷ α) - 1, where α is the angle between the mirrors. The result determines how many images will be reflected based on the angle.

What does it mean when the result of 360 ÷ α is an even number?

If the result of 360 ÷ α is an even number, the images can be projected in various positions. The object can be placed anywhere, and the mirrors will still form images.

What happens if the result of 360 ÷ α is an odd number?

If the result of 360 ÷ α is an odd number, the object must be placed on the bisector of the angle, which is the line that divides the angle exactly in half. This ensures the correct formation of images.

What is an example of an angle where the result of 360 ÷ α is an odd number?

An example of this is when the angle between the mirrors is 90 degrees. Using the formula, 360 ÷ 90 gives 4, and 4 - 1 equals 3, an odd number. Therefore, the object must be placed on the bisector plane of the 90-degree angle for proper reflection.

What happens when two mirrors are placed parallel to each other?

When two mirrors are placed parallel to each other and an object is placed between them, infinite images are formed. This happens because the images reflect back and forth between the mirrors.

How many images are formed when the angle between two mirrors is 90 degrees?

When two mirrors meet at a 90-degree angle, three images of the object are formed, as calculated by the formula: 360 ÷ 90 - 1 = 3.

Why is the bisector of the angle important for image formation in flat mirrors?

The bisector of the angle is important because, when the result of 360 ÷ α is an odd number, the object must be placed along this line. This ensures the correct projection of images formed by the two mirrors.

Can the formula 360 ÷ α - 1 be applied to any angle between two mirrors?

Yes, the formula 360 ÷ α - 1 can be applied to any angle between two flat mirrors to calculate the number of images formed, as long as the angle is between 0 and 180 degrees.

What is the significance of the formula 360 ÷ α - 1 in understanding reflections?

The formula 360 ÷ α - 1 is significant because it allows us to predict how many images will be formed when two mirrors are at a certain angle. By applying this formula, we can understand the behavior of light and reflections in various mirror setups.