Advertisements
Advertisements
Question
With the help of an appropriate ray diagram, state the sign conventions for reflection by a spherical mirror.
Advertisements
Solution
The sign convention for reflection by spherical mirrors is as follows:-
- The object is always placed to the left of the mirror.
- All distances parallel to the principal axis are measured from the pole of the mirror.
- All the distances measured to the right of the origin are taken as positive, while those measured to the left of the origin are taken as negative.
- Distances measured perpendicular to and above the principal axis are taken as positive.
- Distances measured perpendicular to and below the principal axis are taken as negative.
- The focal length of a convex mirror is positive, while that of a concave mirror is negative.
APPEARS IN
RELATED QUESTIONS
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.
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
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
List four characteristics of the images formed by plane mirrors.
The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should the position of the object be relative to the mirror? Draw ray diagram to justify your answer.
Briefly describe how you would find the focal length of a concave mirror quickly but approximately
Give two uses of concave mirrors. Explain why you would choose concave mirrors for these uses.
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 100 mm in front of a concave mirror which produces an upright (erect image). The radius of curvature of the mirror is ______.
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?
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?
According to cartesion sign convention, which mirror and which lens has negative focal length?
In which of the following, the image of an object placed at infinity will be highly diminished and point sized?
A concave mirror produces a magnification of +4. The object is placed ______.
You are provided with a concave mirror, a convex mirror, a concave lens and a convex lens. To obtain an enlarged image of an object you can use either
______ mirrors magnify the object placed close to them.
To obtain an image twice the size of the object, between which two points related to a concave mirror should an object be placed?
Which type of mirror is used in the following?
Shaving mirror
