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Question
A virtual, erect and magnified image of an object is to be produced with a concave mirror of focal length 12 cm. Which of the following object distance should be chosen for this purpose?
(i) 10 cm
(ii) 15 cm
(iii) 20 cm
Give reason for your choi
Solution
The object must be kept at a distance of 10 cm from the concave mirror in order to produce a virtual, erect and magnified image. The reason being, a concave mirror forms a virtual, erect and magnified image when an object is placed between the focus and the pole.
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RELATED QUESTIONS
A student wants to project the image of a candle flame on a screen 90 cm in front of a mirror by keeping the flame at a distance of 15 cm from its pole.
(a) Suggest the type of mirror he should use.
(b) Determine the linear magnification in this case.
(c) Find the distance between the object and its image.
(d) Draw ray diagram to show the image formation in this case
Where should an object be placed in front of the concave mirror so as to obtain its virtual, erect and magnified image?
For which positions of the object does a concave mirror produce an inverted, magnified an real image?
Write down a formula for the magnification produced by a concave mirror.
in terms of object distance and image distance
To obtain a magnification of, –2 with a convex lens of focal length 10 cm, the object should be placed:
(a) between 5 cm and 10 cm
(b) between 10 cm and 20 cm
(c) at 20 cm
(d) beyond 20 cm
If a magnification of, –1 is to be obtained by using a converging lens of focal length 12 cm, then the object must be placed:
(a) within 12 cm
(b) at 24 cm
(c) at 6 cm
(d) beyond 24 cm
An image formed on a screen is three times the size of the object. The object and screen are 80 cm apart when the image is sharply focussed.
Calculate focal length of the lens.
A convex mirror has a focal length of 18 cm. The image of an object kept in front of the mirror is half the height of the object. What is the distance of the object from the mirror?
Magnification for the convex mirror is ______.
Assertion: The focal length of the mirror is /and the distance of the object from the focus is V then the magnification of the mirror will be `("f"/"f−u")`
Reason: Magnification = `"image distance"/ "object distance"` = `(-"v"/"u")`
