Quarter 2 Lesson 2: Qualitative Characteristics of Images Formed by Mirrors PDF

Quarter 2 | Lesson 2 : Qualitative Characteristics of Images Formed by Mirrors What can you see when you look at a mirror, or a polished metal or a still pool of water? You can see your image. Why? These objects are image reflecting objects. A mirror i...

Quarter 2 | Lesson 2 : Qualitative Characteristics of Images Formed by Mirrors What can you see when you look at a mirror, or a polished metal or a still pool of water? You can see your image. Why? These objects are image reflecting objects. A mirror is a smooth reflecting surface, usually made of polished metal or glass that has been coated with metallic substances. There are two types of mirrors: a plane mirror and a curved mirror. Reflection is the bouncing off of light rays when it hits a surface like a plane mirror. In the activity, you used plane mirrors and located the object distance, p and the image distance, q and found out that p is equal to q. In plane mirrors, the image appears as if it is behind the mirror but actually not, so the image is virtual. The value therefore of image distance, q is negative. The height of the image, h’ in plane mirrors is always the same as the height of the object, thus its magnification, M is 1. Incident Ray. The ray of light approaching the mirror represented by an arrow approaching an optical element like mirrors. Reflected Ray. The ray of light which leaves the mirror and is represented by an arrow pointing away from the mirror. Normal Line. An imaginary line that can be drawn perpendicular to the mirror. Types of Reflection 1. Specular / Regular Reflection. This is a reflection of light on smooth surfaces such as mirrors or a calm body of water. 2. Diffused / Irregular Reflection. This is a reflection of light on rough surfaces such as clothing, paper, wavy water, and the asphalt roadway. A curved mirror is a reflecting surface in which its surface is a section of sphere. There are two kinds of curved mirrors, the concave and the convex mirrors. A spoon is a kind of a curved mirror with both concave and convex surfaces. Two Kinds of Spherical Mirrors 1. The Concave Mirror It is a curved mirror in which the reflective surface bulges away from the light source. It is called Converging Mirror because the parallel incident rays converge or meet/intersect at a focal point after reflection. 2. The Convex Mirror It is a curved mirror in which the reflective surface bulges towards the light source. It is called Diverging Mirror because the parallel incident rays diverge after reflection. When extending the reflected rays behind the mirror, the rays converge at the focus behind the mirror. Image Formation by Spherical Mirrors Image Formation by Concave Mirrors Guidelines for Ray Diagramming on the Concave and Convex Mirrors By changing the position of the object from the concave 1. When a ray strikes concave or convex mirrors obliquely at its pole, it mirror, different types of images can be formed. Different is reflected obliquely. types of images are formed when the object is placed: 2. When a ray, parallel to principal axis strikes concave or convex 1. at the infinity mirrors, the reflected ray passes through the focus on the principal 2. beyond the center of curvature axis. 3. at the center of curvature 3. When a ray, passing through focus strikes concave or convex mirrors, 4. between the center of curvature and principal focus the reflected ray will pass parallel to the principal axis. 5. at the principal focus 4. A ray passing through the center of curvature of the spherical mirror 6. between the principal focus and pole will retrace its path after reflection. SECOND QUARTER SCIENCE 10 PAGE 1 of 2 Concave Mirror Ray Diagram Concave Mirror Ray Diagram lets us understand that, when an object is placed at infinity, a real image is formed at the focus. The size of the image is much smaller compared to that of the object. When an object is placed behind the center of curvature, a real image is formed between the center of curvature and focus. The size of the image is smaller than compared to that of the object. When an object is placed at the center of curvature and focus, the real image is formed at the center of curvature. The size of the image is the same as compared to that of the object. When an object is placed in between the center of curvature and focus, the real image is formed behind the center of curvature. The size of the image is smaller than compared to that of the object. When an object is placed at the focus, the real image is formed at infinity. The size of the image is much larger than compared to that of the object. When an object is placed in between focus and pole, a virtual and erect image is formed. The size of the image is larger than compared to that of the object. Image Formation by Convex Mirror The image formed in a convex mirror is always virtual and erect, whatever be the position of the object. In this section, let us look at the types of images formed by a convex mirror. When an object is placed at infinity, a virtual image is formed at the focus. The size of the image is much smaller than compared to that of the object. When an object is placed at a finite distance from the mirror, a virtual image is formed between the pole and the focus of the convex mirror. The size of the image is smaller than compared to that of the object. Exercise 1 : IMAGE IN A PLANE MIRROR 1. Stand in front of a plane mirror. Is your image exactly the same in size as you are? Where is it apparently found? 2. Raise your left hand. What hand does your image raise? 3. Is your image erect or inverted? Is it real or virtual? A real image is an inverted image; a virtual image is an erect image Exercise 2 : MIRROR LEFT-RIGHT REVERSAL Using the following, alphabet chart written in a piece of paper and a plane mirror, do the following: 1. Place the alphabet chart in front of the plane mirror. Identify all capital letters in the alphabet that can be read properly in front of the mirror. 2. Write at least 3 words (all in capital letters) that can be read properly both with a mirror and without a mirror in front of it. Questions: 1. What are the letters of the alphabet (in capital) that can be read properly in front of a mirror? 2. Think of words (in capital letters) that can be read properly both with a mirror and without a mirror. What are these words? 3. Write the sentence below on a clear sheet of paper in such a way that it can be read properly in front of a mirror: Honesty is the best policy. SECOND QUARTER SCIENCE 10 PAGE 2 of 2