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प्रश्न
Define the terms focus and focal length of a concave mirror. Draw diagram to illustrate your answer.
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उत्तर
Focus of a concave mirror: The focus of a concave mirror is a point on the principal axis through which the light rays incident parallel to principal axis, pass after reflection from the mirror.
Focal length of a concave mirror: The distance of the focus from the pole of the concave mirror is called its focal length.
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संबंधित प्रश्न
A ray of light is incident normally on a plane mirror. What will be the:
- angle of incidence?
- angle of reflection?
Name the spherical mirror which can produce a real and diminished image of an object.
- A small object is placed 150 mm away from a diverging lens of focal length 100 mm.
- Copy the figure below and draw rays to show how an image is formed by the lens.
- Calculate the distance of the image from the lens by using the lens formula.
- Copy the figure below and draw rays to show how an image is formed by the lens.
- The diverging lens in part (a) is replaced by a converging lens also of focal length 100 mm. The object remains in the same position and an image is formed by the converging lens. Compare two properties of this image with those of the image formed by the diverging lens in part (a).
How is a spherical mirror used to converge a beam of light at a point? Name the type of mirror used.
What is meant by magnification? Write its expression. What is its sign for the (a) real (b) virtual, image?
Complete the following diagrams shown in the following figures by drawing the reflected rays.
How tall does a mirror have to be to fit an entire person’s body?
A converging lens of focal length f is placed at a distance 0.3 m from an object to produce an image on a screen 0.9 m from the lens. With the object and the screen in the same positions, an image of the object could also be produced on the screen by placing a converging lens of focal length.
