Question

Draw a ray diagram in each case and state whether the image are real or virtual and also if they are

upright or inverted
a. U= 5 cm and f= 2 cm
b. u = 10mm; f = 15mm
c. u = 3 cm ; f = 4 cm

Calculate the position of the images formed by the following concave lenses.
a. For an object with u = 6 cm if the focal length is - 2 cm
b. For an object with u = 4 cm if the focal length is -8 cm
c. For an object with u = 240mm if the focal length is - 8 cm

Answer 1

Explanation:

(i)

O is the object and I is the image.

The image formed is enlarged and it is erect. So the magnification will be positive (+) and greater than 1.

Refer above image. 1

(ii)

O is the object and I is the image.

The image formed is diminished and erect. So the magnification will be positive (+) and less than1.

Refer above image. 2

(iii)

The image will be formed as the 2F on the other side of the lens and it will be of same of the object.

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