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प्रश्न
Why are concave mirrors used in solar devices?
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उत्तर
A concave mirror is also known as a converging mirror because of its ability to focus parallel rays of light at a single point on its focal plane. This property is used in solar devices. Parallel rays from the Sun, when reflected by the concave mirror, are focused at a particular point, generating a significant amount of heat. This heat is essential for the proper functioning of solar devices, such as solar cookers or solar furnaces.
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संबंधित प्रश्न
A student wants to project the image of a candle flame on the walls of the school laboratory by using a mirror.
(a) Which type of mirror should he use and why?
(b) At what distance, in terms of focal length 'f' of the mirror, should he place the candle flame to get the magnified image on the wall?
(c) Draw a ray diagram to show the formation of the image in this case.
(d) Can he use this mirror to project a diminished image of the candle flame on the same wall? State 'how' if your answer is 'yes' and 'why not' if your answer is 'no.'
We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.
The image of a candle flame placed at a distance of 30 cm from a mirror is formed on a screen placed in front of the mirror at a distance of 60 cm from its pole. What is the nature of the mirror? Find its focal length. If the height of the flame is 2.4 cm, find the height of its image. State whether the image formed is erect or inverted.
The angle between an incident ray and the plane mirror is 30°. The total angle between the incident ray and reflected ray will be:
(a) 30°
(b) 60°
(c) 90°
(d) 120°
Draw the following diagram in your answer book and show the formation of image of the object AB with the help of suitable rays:
Briefly describe how you would find the focal length of a concave mirror quickly but approximately
Giving reasons, state the 'signs' (positive or negative) which can be given to the following:
(a) object distance (u) for a concave mirror or convex mirror
(b) image distance (v) for a concave mirror
(c) image distance (v) for a convex mirror
Describe the nature of image formed when the object is placed at a distance of 20 cm from a concave mirror of focal length 10 cm
A concave mirror has a focal length of 4 cm and an object 2 cm tall is placed 9 cm away from it. Find the nature, position and size of the image formed.
An object is placed just outside the principal focus of concave mirror. Draw a ray diagram to show how the image is formed, and describe its size, position and nature.
What type of image/images are formed by:
a convex mirror?
Name the mirror which can give:
an erect and enlarged image of an object.
A student has to determine the focal length of a concave mirror by obtaining the image of a distant object on a screen. For getting best result he should focus
(A) a distant tree or an electric pole
(B) a well-illuminated distant building
(C) well-lit grills of the nearest window
(D) a burning candle laced at the distant edge of the laboratory table
To find the focal length of a concave mirror Rahul focuses a distant object with this mirror. The chosen object should be
(1) a tree
(2) a building
(3) a window
(4) the sun
Pick out the concave and convex mirrors from the following and tabulate them.
Rear-view mirror, Dentist’s mirror, Torchlight mirror, Mirrors in shopping malls, Make-up mirror.
You are provided with a concave mirror, a convex mirror, a concave lens and a convex lens. To obtain an enlarged image of an object you can use either
An erect and enlarged image can be formed by
The focal length of a concave mirror is 5cm. Its radius of curvature is ______.
Which type of mirror is used in the following?
Shaving mirror
