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प्रश्न
Describe the positions of the source of light with respect to a concave mirror in Projector lamp.
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उत्तर
In a projector lamp, the light source is at the centre of the curvature of a concave mirror, which produces an image of the shape of the object itself.
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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.
State two positions in which a concave mirror produces a magnified image of a given object. List two differences between the two images.
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
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.'
The radius of curvature of a spherical mirror is 20 cm. What is its focal length?
Name the mirror that can give an erect and enlarged image of an object.
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?
A spherical mirror and a thin spherical lens have each a focal length of -15 cm. The mirror and the lens are likely to be ______.
Which type of mirror is used by a dentist?
Find the focal length of a concave mirror whose radius of curvature is 32 cm.
A communications satellite in orbit sends a parallel beam of signals down to earth. If these signals obey the same laws of reflection as light and are to be focussed onto a small receiving aerial, what should be the best shape of the metal 'dish' used to collect them?
If an object is placed at the focus of a concave mirror, where is the image formed?
Draw the following diagram in your answer book and show the formation of image of the object AB with the help of suitable rays:
Described with the help of a diagram, the nature, size and position of the image formed when an object is placed beyond the centre of curvature of a concave mirror.
Draw a ray diagram showing how a concave mirror can be used to produce a real, inverted and diminished image of an object.
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
The real image formed by a concave mirror is larger than the object when object is:
(a) at a distance equal to radius of curvature
(b) at a distance less than the focal length
(c) between focus and centre of curvature
(d) at a distance greater than radius of curvature
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
An object is placed at a distance of 10 cm from a concave mirror of focal length 20 cm.
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.
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 virtual image is formed 20 cm from the mirror?
If a concave mirror has a focal length of 10 cm, find the two positions where an object can be placed to give, in each case, an image twice the height of the object.
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 between the pole and focus of a concave mirror. State the position, size and nature of the image.
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.
Draw the ray diagram and also state the position, the relative size and the nature of image formed by a concave mirror when the object is placed at the centre of curvature 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
Match the following.
| Convex mirror | Radio telescopes |
| Parobolic mirror | Rear – view mirror |
| Snell’s law | Kaleidoscope |
| Dispersion of light | sin i/sin r =μ |
| Refractive index | Rainbow |
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 ______.
Beams of light are incident through the holes A and B and emerge out of box through the holes C and D respectively as shown in the figure. Which of the following could be inside the box?
For a real object, which of the following can produce a real image?
A concave mirror of radius 30 cm is placed in water. It’s focal length in air and water differ by ______.
An erect and enlarged image can be formed by
An image formed by a lens is erect. Such an image could be formed by a
In the headlights of motor vehicles, ______ mirrors are used as reflectors.
Which type of mirror is used in the following?
Floodlights
