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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
"A concave mirror of focal length 15 cm can form a magnified, erect as well as inverted image of an object placed in front of it." Justify this statement stating the position of the object with respect to the pole of the mirror in both the cases for obtaining the images.
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.
It is desired to obtain an erect image of an object, using concave mirror of focal length of 12 cm.
Will the image be smaller or larger than the object? Draw ray diagram to show the formation of image in this case.
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
Draw ray diagrams to show the principal focus of a convex mirror.
A student has obtained the image of a distant object with a concave mirror to determine its focal length. If he has selected a well-illuminated red building as object, which of the following correctly describes the features of the image formed?
(A) Virtual, inverted and diminished image in red shade
(B) Real, erect and diminished image in pink shade
(C) Real, inverted and diminished image in red shade
(D) Virtual, erect and enlarged image in red shade
To construct a ray diagram we use two rays which are so chosen that it is easy to know their directions after reflection from the mirror. List two such rays and state the path of these rays after reflection in case of concave mirrors. Use these two rays and draw ray diagram to locate the image of an object placed between pole and focus of a concave 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.
If the focal length of a convex mirror is 25 cm, what is its radius of curvature?
Fill in the following blank with suitable word:
Parallel rays of light are reflected by a concave mirror to a point called the ..........
Fill in the following blank with suitable word:
The focal length of a concave mirror is the distance from the ......... to the mirror.
For a convex mirror, parallel rays of light appear to diverge from a point called the ______.
What is a spherical mirror?
Define the principal focus of 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.
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.
Give two uses of concave mirrors. Explain why you would choose concave mirrors for these uses.
- Draw ray-diagrams to show the formation of images when the object is placed in front of a concave mirror (converging mirror):
- between its pole and focus
- between its centre of curvature and focus.
Describe the nature, size and position of the image formed in each case.
- State one use of concave mirror based on the formation of image as in case (i) above.
The real image formed by a concave mirror is smaller than the object if the object is:
(a) between centre of curvature and focus
(b) at a distance greater than radius of curvature
(c) at a distance equal to radius of curvature
(d) at a distance equal to focal length
When an object is placed at a distance of 15 cm from a concave mirror, its image is formed at 10 cm in front of the mirror. Calculate the focal length of the mirror.
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.
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?
Name the mirror which can give:
an erect and enlarged image of an object.
The mirror used by a dentist to examine the teeth of a person is ______.
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
State two uses of a concave mirror.
Suppose you have three concave mirrors A, B and C of focal lengths 10 cm, 15 cm and 20 cm. For each concave mirror you perform the experiment of image formation for three values of object distance of 10 cm, 20 cm and 30 cm. Giving reason answer the following:
(a) For the three object distances, identify the mirror/mirrors which will form an image of magnification – 1.
(b) Out of the three mirrors identify the mirror which would be preferred to be used for shaving purposes/makeup.
(c) For the mirror B draw ray diagram for image formation for object distances 10 cm and 20 cm.
Large ______ mirrors are used to concentrate sunlight to produce heat in solar furnaces.
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.
A 10 mm long awl pin is placed vertically in front of a concave mirror. A 5 mm long image of the awl pin is formed at 30 cm in front of the mirror. The focal length of this mirror is ______.
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?
For a real object, which of the following can produce a real 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 ______.
While looking at the above diagram, Nalini concluded the following.
- the image of the object will be a virtual one.
- the reflected ray will travel along the same path as the incident ray but in opposite direction.
- the image of the object will be inverted.
- this is a concave mirror and hence the focal length will be negative.
Which one of the above statements are correct?
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?
Between which two points of a concave mirror should an object be placed to obtain a magnification of -2?
