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प्रश्न
Describe the positions of the source of light with respect to a concave mirror in Torch light.
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उत्तर
In a Torch, the light source is at the hub of a concave mirror, which gives you parallel light.
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संबंधित प्रश्न
An object of height 5 cm is placed perpendicular to the principal axis of a concave lens of focal length 10 cm. If the distance of the object from the optical centre of the lens is 20 cm, determine the position, nature and size of the image formed using the lens formula.
Draw ray diagrams to show the principal focus of a convex mirror.
An object is placed at a distance of 12 cm in front of a concave mirror of radius of curvature 30 cm. List four characteristics of the image formed by the mirror.
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°
Find the focal length of a concave mirror whose radius of curvature is 32 cm.
For what position of an object, a real and diminished image is formed by a concave mirror?
Explain why, a ray of light passing through the centre of curvature of a concave mirror gets reflected back along the same path.
If an object is placed at a distance of 8 cm from a concave mirror of focal length 10 cm, discuss the nature of the image formed by drawing the ray diagram.
With the help of a labelled ray diagram, describe how a converging mirror can be used to give an enlarged upright image of an object.
Explain why, concave mirrors are used as shaving mirrors.
The angle of incidence for of light passing through the centre of curvature of a concave mirror is:
(a) 45°
(b) 90°
(c) 0°
(d) 180°
According to the "New Cartesian Singh Convention" for mirrors, what sign has been given to the focal length of:
a convex mirror?
What kind of mirror can have a focal length of, −20 cm?
A converging mirror forms a real image of height 4 cm of an object of height 1 cm placed 20 cm away from the mirror:
- Calculate the image distance.
- What is the focal length of the mirror?
An object 3 cm high is placed at a distance of 10 cm in front of a converging mirror of focal length 20 cm. Find the position, nature, and size of the image formed.
How far should an object be placed from the pole of a converging mirror of focal length 20cm to form a real image of the size exactly `1/4`th the size of the object?
At what distance from a concave mirror of focal length 10 cm should an object be placed so that:
its real image is formed 20 cm from the mirror?
At what distance from a concave mirror of focal length 10 cm should an object be placed so that:
- its real image is formed 20 cm from the mirror?
- its virtual image is formed 20 cm from the mirror?
Which of the following are concave mirrors and which convex mirrors?
Shaving mirrors, Car headlight mirror, Searchlight mirror, Driving mirror, Dentist’s inspection mirror, Torch mirror, Staircase mirror in a double-decker bus, Make-up mirror, Solar furnace mirror, Satellite TV dish, Shop security mirror.
A concave mirror cannot be used as:
(a) a magnifying mirror
(b) a torch reflector
(c) a dentist's mirror
(d) a real view mirror
An object is placed 15 cm from (a) a converging mirror, and (b) a diverging mirror, of radius of curvature 20 cm. Calculate the image position and magnification in each case.
Draw a ray diagram to show the formation of image of an object placed at the centre of curvature of a concave mirror. State the position, size and nature of the image.
State two uses of a concave mirror.
In the following diagram. MM' is a concave mirror and AB is an object. Draw on your answer-sheet a ray diagram to show the formation of image of this object.
To construct ray diagram we use two light rays which are so chosen that it is easy to know their directions after reflection from the mirror. List these two rays and state the path of these rays after reflection. Use these rays to locate the image of an object placed between centre of curvature and focus of a concave mirror.
Why does obtaining the image of the sun on paper with the help of a concave mirror burn the paper?
A _____________ mirror is used by a dentist.
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
Which of the following mirror is used by a dentist to examine a small cavity in a patient’s teeth?
Rays from Sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of its image is equal to the size of the object?
Identify the device used as a spherical mirror or lens in following case, when the image formed is virtual and erect in case.
Object is placed between device and its focus, image formed is enlarged and behind it.
The image formed by a concave mirror is real, inverted and of the same size as that of the object, the position of the object should be ______.
A student took three concave mirrors of different focal lengths and performed the experiment to see the image formation by placing an object at different distance with these mirrors as shown in the following table.
| Case No. | Object-distance | Focal length |
| I | 45 cm | 20 cm |
| II | 30 cm | 15 cm |
| III | 20 cm | 30 cm |
Now answer the following questions:
(a) List two properties of the image formed in Case I.
(b) In which one of the cases given in the table, the mirror will form real image of same size and why?
(c) Name the type of mirror used by dentists. Given reason why do they use such type of mirrors.
OR
(c) Look at the table and identify the situation (object distance and focal length) which resembles the situation in which concave mirrors are used as shaving mirrors? Draw a ray diagram to show the image formation in this case.
