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Q.11. An object 2 cm in size is placed 30 cm in front of a concave mirror of focal length 15 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image? What will be the nature and the size of the image formed? Draw a ray diagram to show the formation of the image in this case. 3

Sol. Size of the Object, h₁ = + 2 cm
Object distance, u = – 30 cm
Concave mirror : focal length, f = – 15 cm
Image distance, v = ?
= Size of the image, h₂ = ?
Nature of the image = ?

According to mirror formula

-ve sign of v shows that image is formed 30 cm in front of the mirror therefore the image is real.
According to magnification formula

Q.12. The position of three elements A, B and C in the Periodic Table are shown below :

Science 2008 Question Papers Class X
Delhi		Outside Delhi		Compartment Delhi		Compartment Outside Delhi
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