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प्रश्न
Why does obtaining the image of the sun on paper with the help of a concave mirror burn the paper?
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उत्तर
The rays from the Sun are parallel. When these rays fall on the concave mirror, they converge to a single point on the focal plane of the mirror. Thus, a lot of heat is produced at that point. Now, if a paper is placed at that point to get the image of the Sun, the paper gets burnt because of the huge amount of heat concentrated at that point.
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संबंधित प्रश्न
It is desired to obtain an erect image of an object, using concave mirror of focal length of 12 cm.
Where will the image of this object be, if it is placed 24 cm in front of the mirror? Draw ray diagram for this situation also justify your answer. Show the positions of pole, principal focus and the centre of curvature in the above ray diagrams
The radius of curvature of a spherical mirror is 20 cm. What is its focal length?
A concave mirror produces three times magnified image on a screen. If the object is placed 20 cm in front of the mirror, how far is the screen from the object.
State where an object must be placed so that the image formed by a concave mirror is:
(b) at infinity.
(c) the same size as the object.
Make labelled ray diagrams to illustrate the formation of:
- a real image by a converging mirror.
- a virtual image by a converging mirror.
Mark clearly the pole, focus, centre of curvature and position of object in each case.
Make labelled ray diagrams to illustrate the formation of:
a virtual image by a converging mirror.
Mark clearly the pole, focus, centre of curvature and position of object in each case.
Briefly describe how you would find the focal length of a concave mirror quickly but approximately
Explain why, concave mirrors are used as shaving mirrors.
An object is placed at a distance of 10 cm from a concave mirror of focal length 20 cm.
State two characteristics of the image formed.
Which of the following are concave mirrors and which convex mirrors?
A student obtained a sharp inverted image of a distant tree on a screen placed in front of the concave mirror. He then removed the screen and tried to look into the mirror. He would now see
(A) a very blurred image on the wall opposite to the mirror
(B) an erect and magnified image of the tree in the mirror
(C) no image as the screen has been removed
(D) a highly diminished inverted image of the tree at the focus of the mirror.
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
Consider the following properties of virtual images:
- cannot be projected on the screen
- are formed by both concave and convex lens
- are always erect
- are always inverted
The correct properties are:
State whether true or false. If false, correct the statement.
When an object is at the centre of curvature of concave mirror the image formed will be virtual and erect.
The radius of curvature of a concave mirror whose focal length is 5cm is ______
Large ______ mirrors are used to concentrate sunlight to produce heat in solar furnaces.
Name the mirror(s) that can give (i) an erect and enlarged image, (ii) same sized, inverted image
A concave mirror of focal length 20 cm forms an image having twice the size of object. For the virtual position of object, the position of object will be at ______.
Under which of the following conditions a concave mirror can form an image larger than the actual object?
A student wants to obtain an erect image of an object using a concave mirror of 10 cm focal length. What will be the distance of the object from mirror?
