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प्रश्न
Describe the positions of the source of light with respect to a concave mirror in Floodlight.
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उत्तर
In a floodlight, the light source is slightly beyond the radius of curvature, which gives us the right light.
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संबंधित प्रश्न
Draw a ray diagram for concave mirror when the object is between centre of curvature and focus.
Draw a ray diagram to show the path of the refracted ray in each of the following cases:-
A ray of light incident on a concave lens is
(i) passing through its optical centre.
(ii) parallel to its principal axis.
(iii) directed towards its principal focus.
Draw ray diagrams to show the principal focus of a concave mirror.
The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should the position of the object be relative to the mirror? Draw ray diagram to justify your answer.
A concave mirror produces three times magnified (enlarged) real image of object placed at 10 cm in front of it. Where is the image located?
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.
Fill in the following blank with suitable word:
The focal length of a concave mirror is the distance from the ......... to the mirror.
Draw the following diagram in your answer book and show the formation of image with the help of suitable rays:
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.
Draw a ray diagram showing how a concave mirror can be used to produce a real, inverted and diminished image of an object.
Name the type of mirror used by dentists. How does it help?
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°
The focal length of a small concave mirror is 2.5 cm. In order to use this concave mirror as a dentist's mirror, the distance of tooth from the mirror should be:
(a) 2.5 cm
(b) 1.5 cm
(c) 4.5 cm
(d) 3.5 cm
What is the position of the image when an object is placed at a distance of 20 cm from a concave mirror of focal length 20 cm?
If an object of 10 cm height is placed at a distance of 36 cm from a concave mirror of focal length 12 cm, find the position, nature and height of the image.
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.
A man holds a spherical shaving mirror of radius of curvature 60 cm, and focal length 30 cm, at a distance of 15 cm, from his nose. Find the position of image, and calculate the magnification.
If the object is moved further away from the mirror, what changes are there in the position and size of the image?
An object is placed at a large distance in front of a concave mirror of radius of curvature 40 cm. The image will be formed in front of the mirror at a distance:
(a) 20 cm
(b) 30 cm
(c) 40 cm
(d) 50 cm
What would your image look like if you stood close to a large:
concave mirror?
Which of the following are concave mirrors and which convex mirrors?
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
The image formed by a concave mirror is of the same size as the object, if the object is placed
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.
A student obtained a sharp image of the grills of a window on a screen using a concave mirror. His teacher remarked that for getting better results a well lit distant object (preferably the sun) should be focussed on the screen. What should be done for this purpose?
(A) Move the screen slightly away from the mirror
(B) Move the mirror slightly towards the screen
(C) Move the screen and the mirror away from the object
(D) Move the screen and the mirror towards the object
A student has to trace the path of a ray of light passing through a rectangular glass slab for four different values of angle of incidence.
(a) Write two important precautions for this experiment.
(b) List two conclusions the student will draw based on his experiment.
Choose the correct option from given alternative:
Consider the following properties of virtual images:
(A) cannot be projected on the screen
(B) are formed by both concave and convex lens
(C) are always erect
(D) are always inverted
______ is used as reflectors in torchlight.
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.
For a real object, which of the following can produce a real image?
Examine the above figure and state which of the following option is correct? [one small box in the figure is equal to 1 cm]
Under which of the following conditions a concave mirror can form an image larger than the actual object?
Write the uses of the concave mirror.
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?
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.
