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प्रश्न
Describe the positions of the source of light with respect to a concave mirror in Torch light.
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
If the image formed by a mirror for all positions of the object placed in front of it is always erect and diminished, what type of mirror is it? Draw a ray diagram to justify your answer. Where and why do we generally use this type of mirror?
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.
To determine the approximate value of the focal length of a given concave mirror, you focus the image of a distant object formed by the mirror on a screen. The image obtained on the serene, as compared to the object is always:
(a) Laterally inverted and diminished
(b) Inverted and diminished
(c) Erect and diminished
(d) Erect and highly diminished
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.
A student obtained a sharp image of a candle flame placed at the distant end of the laboratory table on a screen using a concave mirror to determine its focal length. The teacher suggested him to focus a distant building, about 1 km away from the laboratory, for getting more correct value of the focal length. In order to focus the distant building on the same screen, the student should slightly move the
(a) mirror away from the screen
(b) screen away from the mirror
(c) screen towards the mirror
(d) screen towards the building
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
Three students A, B and C focussed a distant building on a screen with the help of a concave mirror. To determine focal length of the concave mirror they measured the distances as given below:
Student A : From mirror to the screen
Student B : From building to the screen
Student C : From building to the mirror
Who measured the focal length correctly ;
(a) Only A
(b) Only B
(c) A and B
(d) B and C
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.
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:
The focal length of a concave mirror is the distance from the ......... to the mirror.
For what position of an object, a concave mirror forms a real image equal in size to the object?
Which kind of mirror is used in the headlights of a car? Why is it used for this purpose?
Explain why, a ray of light passing through the centre of curvature of a concave mirror gets reflected back along the same path.
What is the minimum number of rays required for locating the image formed by a concave mirror for an object? Draw a ray diagram to show the formation of a virtual image by 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 real image by a converging mirror.
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.
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 concave mirror?
Write down a formula for the magnification produced by a concave mirror.
in terms of height of object and height of image
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?
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 concave mirror produces a real image 1 cm tall of an object 2.5 mm tall placed 5 cm from the mirror. Find the position of the image and the focal length of the mirror.
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 24 cm away from a concave mirror and its image is 16 cm from the mirror. Find the focal length and radius of curvature of the mirror, and the magnification 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
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.
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 real image of an object is to be obtained. The mirror required for this purpose is:
(a) convex
(b) concave
(c) plane
(d) either convex or concave
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.
Why does a beam of light when it enters glass at an angle? Why does it not bend if it inters the glass at right angles?
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.
Draw a ray diagram to show the formation of image of an object placed on the principal axis of a convex mirror. State the position, size and nature of the image. What happens to the image as the object is moved away from the mirror?
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.
A student has to determine the focal length of a concave mirror by obtaining the image of a distant object on a screen. For getting best result he should focus
(A) a distant tree or an electric pole
(B) a well-illuminated distant building
(C) well-lit grills of the nearest window
(D) a burning candle laced at the distant edge of the laboratory table
A child is standing in front of a magic mirror. She finds the image of her head bigger, the middle portion of her body of the same size and that of the legs smaller. The following is the order of combinations for the magic mirror from the top.
The mirror having reflecting surface curved inwards ______.
A concave mirror produces a magnification of +4. The object is placed ______.
An object at a distance of 30 cm from a
concave mirror gets its image at the same point. The focal length of the mirror is ______.
The image formed by concave mirror is real, inverted and of the same size as that of the object. The position of object should be ______.
Which of the following mirror is used by a dentist to examine a small cavity in a patient’s teeth?
You are provided with a convex mirror, a concave mirror, a convex lens and a concave lens. You can get an inverted image from
An image formed by a lens is erect. Such an image could be formed by a
State whether the following statement is True or False
The sides of an object and its image formed by a concave mirror are always interchanged.
The concave reflecting surface of a torch got rusted. What effect would this have on the beam of light from the torch?
The ENT doctor uses a ______.
In the headlights of motor vehicles, ______ mirrors are used as reflectors.
The focal length of a concave mirror is 5cm. Its radius of curvature is ______.
Between which two points of a concave mirror should an object be placed to obtain a magnification of -2?
Which type of mirror is used in the following?
Floodlights
