An object of height 7 cm is kept at a distance of 25 CM in front of a concave mirror . The focal length of the mirror is 15 cm. At what distance from the mirror should a screen be kept so as to get a clear image? What will be the size and nature of image

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Solution

We use the curved mirror formulae to get the image distance.:

1/f=1/v+1/u

V is object distance and u is image distance.
F is the focal length.

Substituting the values :1/15=1/25+1/u
1/u=1/15-1/25=5-3/75=2/75

U=75/2=37.5cm

We use the object distance and the image distance to get the magnification.

M=37.5/25=×1.5

The image size =1.5×7=10.5cm

The image is real.

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Similar questions

Q. An object of size (height)

7 c m

is placed at

25 c m

in front of concave mirror of focal length

15 c m

. At what distance from the mirror should a screen be placed, so that we can get a sharp and clear image? Find nature and size (height) of the image.

Solve the following examples

a. An object of height 7 cm is kept at a distance of 25 cm in front of a concave mirror. The focal length of the mirror is 15 cm. At what distance from the mirror should a screen be kept so as to get a clear image? What will be the size and nature of the image?

b. 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?

c. A 10 cm long stick is kept in front of a concave mirror having focal length of 10 cm in such a way that the end of the stick closest to the pole is at a distance of 20 cm. What will be the length of the image?

Solve:

(1) An object of size 7 cm is placed at 25 cm in front of concave mirror of focal length 15 cm. At what distance from the mirror should a screen be placed, so that we can get a sharp and clear image. Find nature and size of the image.

(2) An object of height 5 cm is held 20 cm away from converging lens of focal length 10 cm. Find the position, nature and size of the image formed.

(3) An object is placed at a distance of 10 cm from a convex lens of focal length 12 cm. Find the position and nature of the image.

An object 4 cm in size is placed at a distance of 25 cm from a concave mirror of focal length 15 cm. At what distance from the mirror should the screen be kept so that a sharp image of the object can be obtained on screen? Find the nature and height of the image.

Q. An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed so that a sharp focussed image can be obtained? Find the size and nature of image.

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