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Questions
Describe the positions of the source of light with respect to a concave mirror in Torch light.
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Solution
In a Torch, the light source is at the hub of a concave mirror, which gives you parallel light.
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RELATED QUESTIONS
It is desired to obtain an erect image of an object, using concave mirror of focal length of 12 cm.
What should be the range of distance of an object placed in front of the mirror?
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.
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
State two positions in which a concave mirror produces a magnified image of a given object. List two differences between the two images.
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
Name the type of mirror used in the following situation:
Headlights of a car
Support your answer with reason.
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.
Find the focal length of a concave mirror whose radius of curvature is 32 cm.
If the focal length of a convex mirror is 25 cm, what is its radius of curvature?
For a convex mirror, parallel rays of light appear to diverge from a point called the ______.
Define the principal focus of a concave mirror.
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?
With the help of a ray diagram, determine the position, nature and size of the image formed of an object placed at the centre of curvature of a concave mirror.
State where an object must be placed so that the image formed by a concave mirror is:
(b) at infinity.
(c) the same size as the object.
With the help of a labelled ray diagram, describe how a converging mirror can be used to give an enlarged upright image of an object.
Make labelled ray diagrams to illustrate the formation of:
- a real image by a converging mirror.
- a virtual image by a converging mirror.
Mark clearly the pole, focus, centre of curvature and position of object in each case.
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
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°
An object is placed at the following distances from a concave mirror of focal length 15 cm, turn by turn:
(a) 35 cm
(b) 30 cm
(c) 20 cm
(d) 10 cm
Which position of the object will produce:
(i) a magnified real image?
(ii) a magnified virtual image?
(iii) a diminished real image?
(iv) an image of same size as the object?
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
An object is placed at a distance of 10 cm from a concave mirror of focal length 20 cm.
State two characteristics of the image formed.
At what distance from a concave mirror focal length 10 cm should an object 2 cm long be placed in order to get an erect image 6 cm tall?
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.
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 real image is formed 20 cm from the mirror?
- its virtual image is formed 20 cm from the mirror?
A convex mirror is used as a shaving mirror.
Draw a ray diagram to show the formation of the image of an object placed beyond the centre of curvature 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.
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.
Concave mirrors are used by dentists to examine teeth. Why?
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?
The mirror having reflection surface curved outward ______.
A concave mirror of radius 30 cm is placed in water. It’s focal length in air and water differ by ______.
Which of the following mirror is used by a dentist to examine a small cavity in a patient’s teeth?
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?
The concave reflecting surface of a torch got rusted. What effect would this have on the beam of light from the torch?
Between which two points of a concave mirror should an object be placed to obtain a magnification of -2?
To obtain an image twice the size of the object, between which two points related to a concave mirror should an object be placed?
