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प्रश्न
When an object of height 1 cm is kept at a distance 4 cm from a concave mirror, its erect image of height 1.5 cm is formed at a distance 6 cm behind the mirror. Find the focal length of mirror, by drawing.
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उत्तर
A ray passing parallel to the principal axis passes through the focal point after reflection. Hence, the focal length is 12 cm.
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संबंधित प्रश्न
Explain the following term related to spherical lenses:- optical centre
An image formed by a ______ mirror is always of the same size as that of the 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).
State the two kinds of spherical mirror and distinguish them with the aid of proper diagrams.
Which are the two convenient rays that are chosen to construct the image by a spherical mirror for a given object? Explain with the help of suitable ray diagrams.
Name the two kinds of spherical mirrors and distinguish between them.
For what position of object, the image formed by a concave mirror is magnified and erect?
If the focal length of a spherical mirror is 10 cm, what is the value of its radius of curvature?
If the real image of a candle flame formed by a lens is three times the size of the flame and the distance between lens and image is 80 cm, at what distance should the candle be placed from the lens?
Visit a nearby hospital. You can also visit the clinic of an ENT specialist, or a dentist. Request the doctor to show you the mirrors used for examining ear, nose, throat and teeth. Can you recognise the kind of mirror used in these instruments?
