Que:2:- explain focus of concave and convex mirror using ray diagram.
Answers
Answer:
Concave and Convex Mirrors – Ray Diagrams, Image Formation, Applications
Light is responsible for anything around us visible. This happens when light rays are reflected to the observer from the source object. For a good reflection, the light source must be a polished or shiny surface that acts as a mirror. This is due to the phenomenon called reflection of light which does not intend to change the velocity of light it only reverses the direction of light incident on it. In order to obtain a good reflection of light, the surface chosen for the same must be spherical, smooth & shiny. Therefore, the mirror that is known as a spherical mirror is made out by cutting out a hollow spherical glass ball. A spherical mirror has a reflecting surface that can be inside or outside, it depends on the purpose of use.
Spherical Mirrors
The curved surface we see of a shining spoon can be considered as a curved mirror. The most widely used type of curved mirror is the spherical mirror. The reflecting surface of such mirrors is considered to form a part of the surface of any sphere. Those mirrors which possess reflecting surfaces which are spherical are called spherical mirrors.
Types of Spherical Mirrors
Spherical Mirrors are categorized into two types:
Concave Mirrors
Convex Mirrors
Concave Mirror
If a hollow sphere is cut into some parts and the outer surface of the cut part is painted, then it turns out to be a mirror with its inner surface as the reflecting surface. This makes a concave mirror.
A concave mirror or converging mirror is a type of mirror that is bent towards the inwards side in the middle. Moreover, by looking in this mirror, we will feel that we are looking in a cave. We tend to use the mirror equation to deal with a concave mirror.
The equation for these mirrors determines position of the object and the accurate size of the object. The angle of incidence in the concave mirror is not same as the angle of reflection. Moreover, the angle of reflection in this case depends on the area on which the light hits.
Properties of Concave Mirrors:
Light after reflection converges at a point when it strikes and reflects back from the reflecting surface of the concave mirror. Hence, it is also termed as converging mirror.
When the converging mirror is placed very near to the object, a magnified and virtual image is observed.
But, if we tend to increase the distance between the object and the mirror then the size of the image reduces and a real image is formed.
The image formed by the concave mirror can be small or enlarged or can be either real or virtual.
Applications of Concave Mirrors:
Concave mirror used in the ophthalmoscope
Uses of concave mirror in astronomical telescopes
Concave mirrors used in the headlights
Used in solar furnaces
Image Formation By Concave Mirror And Their Ray Diagrams
When the object is kept at infinity:
As the parallel rays coming from the object converge at the principal focus, F of a concave mirror; after reflection through it. Therefore, when the object is at infinity the image will form at F.
Object at Infinity
Properties of the image formed: Point-sized image, highly diminished in size, Real and inverted image.
When the object is placed between infinity and Centre of Curvature:
When the object is placed between infinity and the centre of curvature of a concave mirror then the image is formed between centre of curvature (C) and focus (F).
Object between Infinity and C
Properties of image: It is diminished as compared to the object and alsoreal and inverted.
Object at Centre of Curvature (C):
Whenever we place our object at the centre of curvature (C) of a concave mirror, we get a real and inverted image formed at the same position.
Object at C
Properties of image: It is of the same size as object and also real and inverted.
Object kept between the Centre of curvature (C) and Principal Focus (F):
When we keep the object somewhere between the center of curvature and the principal focus of the concave mirror, a real image is formed placed beyond the centre of curvature (C).
Object at Principal Focus (F):
When the object is placed at the principal focus (F) of a concave mirror, a highly enlarged image of object is formed at infinity.
Properties of image: Highly enlarged image, its nature is real and inverted
Object between Principal Focus (F) and Pole (P):
When the object is placed anywhere between the principal focus and the pole of a concave mirror, we get an enlarged, virtual and erect image formed behind the mirror.
Object between F and P
Answer:
It is the point on the principal axis of which all the parallel rays coming from infinity actually converge in case of concave or appear to converge in case of convex after reflection from respective mirror.
Explanation:
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