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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
"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.
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
Consider the following diagram in which M is a mirror and P is an object and Q is its magnified image formed by the mirror.
State the type of the mirror M and one characteristic property of the image Q.
List four specific characteristics of the images of the objects formed by convex mirrors.
To construct ray diagrams, two rays of light are generally so chosen that it is easy to determine their directions after reflection from a mirror. Choose two such rays and state the path/direction of these rays after reflection from a concave mirror. Use these two rays to find the position and nature of the image of an object placed at a distance of 8 cm from a concave mirror of focal length 12 cm.
A student wants to project the image of a candle flame on a screen 48 cm in front of a mirror by keeping the flame at a distance of 12 cm from its pole.
(a) Suggest the type of mirror he should use.
(b) Find the linear magnification of the image produced.
(c) How far is the image from its object?
(d) Draw ray diagram to show the image formation in this case.
A ray of light is incident on a plane mirror making an angle of 90° with the mirror surface. The angle of reflection for this ray of light will be:
(a) 45°
(b) 90°
(c) 0°
(d) 60°
Out of convex mirror and concave mirror, whose focus is situated behind the mirror?
Which kind of mirror is used in the headlights of a car? Why is it used for this purpose?
Draw a ray diagram showing how a concave mirror can be used to produce a real, inverted and diminished image of an object.
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
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°
One of the following does not apply to a concave mirror this is:
(a) focal length is negative
(b) image distance can be positive or negative
(c) image distance is always positive
(d) height of image can be positive or negative
Write down a formula for the magnification produced by a concave mirror.
in terms of height of object and height of image
An object is placed at a distance of 10 cm from a concave mirror of focal length 20 cm.
An object is placed at a distance of 10 cm from a concave mirror of focal length 20 cm.
Calculate the image distance.
A bright object 50 mm high stands on the axis of a concave mirror of focal length 100 mm and at a distance of 300 mm from the concave mirror. How big will the image be?
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.
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
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?
The diagram shows a dish antenna which is used to receive television signals from a satellite. The antenna (signal detector) is fixed in front of the curved dish.
Figure
(a) What is the purpose of the dish?
(b) Should it be concave or convex?
(c) Where should the antenna be positioned to receive the strongest possible signals?
(d) Explain what change you would expect in the signals if a larger dish was used.
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.
How can a concave mirror be used to obtain a virtual image of an object? Draw a diagram to illustrate your answer.
A student has focused the image of a candle flame on a white screen using a concave mirror. The situation is as given below:
Length of the flame = 1.5 cm
Distance of flame from the mirror = 18 cm
If the flame is perpendicular to the principal axis of the mirror, then calculate the following:
- Distance of the image from the mirror
- Length of the image
If the distance between the mirror and the flame is reduced to 10 cm, then what would be observed on the screen? Draw ray diagram to justify your answer for this situation.
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.
Answer the following question:
An object is placed at a distance of 30 cm from a concave lens of focal length 30 cm.
(i) Use the lens formula to determine the distance of the image from the lens.
(ii) List four characteristics of the image (nature, position, size, erect/inverted) in this case.
(iii) Draw a labelled diagram to justify your answer of the part (ii)
The mirror used by the ophthalmologist to examine the eye is _______.
______ is used as reflectors in torchlight.
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
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?
The mirror having reflecting surface curved inwards ______.
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 ______.
______ mirrors make things look larger when objects are placed close to them.
______ mirrors magnify the object placed close to them.
Define principal focus of the concave mirror.
