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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
A student used a device (X) to obtain/focus the image of a well illuminated distant building on a screen (S) as shown below in the diagram. Select the correct statement about the device (X).
A student focused the Sun rays using an optical device 'X' on a screen S as shown.
From this it may be concluded that the device 'X' is a (select the correct option)
(A) Convex lens of focal length 10 cm.
(B) Convex lens of radius of curvature 20 cm.
(C) Convex lens of focal length 20 cm.
(D) Concave mirror of focal length 20 cm.
When a spherical mirror is held towards the sun and its sharp image is formed on a piece of a carbon paper for some time, a hole is burnt in the carbon paper.
Why is a hole burnt in the carbon paper?
When a spherical mirror is held towards the sun and its sharp image is formed on a piece of a carbon paper for some time, a hole is burnt in the carbon paper.
What name is given to the distance between spherical mirror and carbon paper?
A concave lens produces an image 20 cm from the lens of an object placed 30 cm from the lens. The focal length of the lens is:
(a) 50 cm
(b) 40 cm
(c) 60 cm
(d) 30 cm
Explain the following terms :
Pole, Centre of curvature, Radius of curvature, Principal axis. Show them on separate diagrams for each of the concave and convex mirrors.
State the kind of mirror used
(a) by a dentist, and
(b) as a street light reflector.
Define the terms pole, principal axis and centre of curvature with reference to a spherical mirror.
What type of mirror can be used to obtain a real image of an object?
What is meant by magnification? Write its expression. What is its sign for the (a) real (b) virtual, image?
State two uses of a concave mirror.
The image formed by a convex mirror is
A concave mirror forms a real image of an object placed in front of it at a distance 30 cm, of size three times the size of object. Find
- the focal length of mirror
- position of image.
An object 5 cm high is placed at a distance 60 cm in front of a concave mirror of focal length 10 cm. Find the position and size of the image.
The sun is seen before the sunrise and after the sunset.
Select the correct option:
Which mirror is used in periscope?
Define the following term:
concave mirror
Define the term principal focus in case of convex mirror. Draw a convex mirror and show its principal focus and focal length clearly.
What do you understand by the term real image?
The following figure shows a concave mirror with its pole (P), focus (F), and center of curvature (C). Draw a ray diagram to show the formation of the image of an object AB by the concave mirror.
Draw a ray diagram to show that a convex mirror has a wider field of view.
The distance from the pole to the focus is called ______.
Numerical problem.
The radius of curvature of a spherical mirror is 25 cm. Find its focal length.
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?
What is the focal length (f) of a mirror?
