Question

an object 2 m tall is placed on the principal axis of a convex lens and it's 40cm tall images formed on the screen placed. at a distance of 72cm from the object what is the focal length of the lens​

Answer 1

Answer:

h

1

=2cm

f=5cm

u=−10m=−1000cm

v

1

−

u

1

=

f

1

v

1

−

−1000

1

=

5

1

v

1

=

5

1

−

1000

1

=

1000

200−1

=

1000

199

v=5.02cm

The image is formed 5.02cm behind the convex lens and is real and inverted.

m=

u

v

=

−1000

5.02

=−0.005

m=

h

1

h

2

=−0.005

2

h

2

=−0.005

h

2

=0.01cm

Since the object distance is much greater than the focal length , this example illustrate the case when the object is place.

Explanation:

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