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Questions
What is a virtual image?
What are virtual images?
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Solution
When the rays of light reflecting from an object appear to meet in a virtual form, then the images formed in this way are called virtual images.
RELATED QUESTIONS
One half of a convex lens of focal length 10 cm is covered with a black paper. Can such a lens produce an image of a complete object placed at a distance of 30 cm from the lens? Draw a ray diagram to justify your answer. A 4 cm tall object is placed perpendicular to its principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 15 cm. Find the nature, position and the size of the image.
Explain the following term related to spherical lenses:- centres of curvature
Match the items given in Column I with one or more items of Column II.
| Column I | Column II | ||
| (a) | A plane mirror | (i) | Used as a magnifying glass. |
| (b) | A convex mirror | (ii) | Can form image of objects spread over a large area. |
| (c) | A convex lens | (iii) | Used by dentists to see enlarged image of teeth. |
| (d) | A concave mirror | (iv) | The image is always inverted and magnified. |
| (e) | A concave lens | (v) | The image is erect and of the same size as the object. |
| (vi) | The image is erect and smaller in size than the object. |
Give one use each of a concave and a convex mirror.
What is the name of the phenomenon in which the right side of an object appears to be the left side of the image in a plane mirror?
Name the spherical mirror which has:
(a) virtual principal focus.
(b) real principal focus.
The shiny outer surface of a hollow sphere of aluminium of radius 50 cm is to be used as a mirror:
Which type of spherical mirror will it provide?
State the two kinds of spherical mirror and distinguish them with the aid of proper diagrams.
The letters on the front of an ambulance are written laterally inverted like 
. Give reason.
State the number of images of an object placed between two mirrors, formed in each case when mirrors are inclined to each other at (a) 90°, and (b) 60°.
Explain the meaning of the terms focus and focal length in case of a convex mirror, with the help of suitable ray diagram.
State the two convenient rays that are chosen to construct the image by a spherical mirror for a given object? Explain your answer with the help of suitable ray diagrams.
For an incident ray directed towards centre of curvature of a spherical mirror the reflected ray:
The image formed by a convex mirror is
A point light source is kept in front of a convex mirror at a distance of 40 cm. The focal length of the mirror is 40 cm. Find the position of image.
At what distance from a concave mirror of focal length 25 cm should an object be placed so that the size of image is equal to the size of the object.
Answer the following question.
Write the modification in the curvature of the eye lens which enables us to see the nearby objects clearly?
What is the relationship between the focal length and radius of curvature?
Complete the following diagrams shown in the below figure by drawing the reflected ray for each incident ray.
Geometric centre of the spherical mirror is ______.
Assertion: Incident ray is directed towards the centre of curvature of spherical mirror. After reflection it retraces its path.
Reason: Angle of incidence (i) = Angle of reflection (r) = 0°
If the real image of a candle flame formed by a lens is three times the size of the flame and the distance between lens and image is 80 cm, at what distance should the candle be placed from the lens?
Name the type of mirror used in the following situation:
Solar furnace
Support your answer with reason.
The distance from the center of curvature of the mirror to the pole is called the focal length of the mirror.
What is the focal length (f) of a mirror?
Visit a nearby hospital. You can also visit the clinic of an ENT specialist, or a dentist. Request the doctor to show you the mirrors used for examining ear, nose, throat and teeth. Can you recognise the kind of mirror used in these instruments?
