MyQuestionIcon

4

You visited us 4 times! Enjoying our articles? Unlock Full Access!

Image in Thin Lens by Ray Tracing

3 lenses L1, ...

Question

3 lenses L1, L2 and L3 each of focal length 30 cm are placed coaxially .an object is held at 60cm from the optical centre of lens L1.the final image is formed at the focus os L3.Calculate the separation between 1) L1 and L2 2) L2 and L3

Open in App

Solution

F1=f2=f3=30cm
1/f1= 1/v1-1/u1
1/v1=1/f1 +1/u1
= 1/30-1/60
= 1/60
v1=60cm
now image by L3 is formed at focus.
thus object for L3 is placed at infinity.
and hence image firmed by L2 is at infinity.
thus u2= 30cm
object for L2 is placed. at 30cm left from L2 which is 60cm right from L1 as image of L1 is formed at 60cm right of L1

so X1 = distance between L1 and L2
=v1+ u2=60+30= 90cm
Therefore L2 make s image at infinity , any distance between L2 and L3 will make the object for L3 as infinity.
L2 and L3 = any length

Suggest Corrections

thumbs-up

15

Similar questions

Q. You are given three lens

L_{1}, L_{2}, L_{3}

each of focal length

15 c m

. An object is kept at

20 c m

L_{1}

, as shown. The final real image is formed at the focus

^{'} I^{'}

L_{3}

. Find the separations between

L_{1}, L_{2}

L_{3}

.

Q. Three lenses

L_{1}, L_{2}, L_{3}

are placed co-axially as shown in figure. Focal length's of lenses are given 30 cm, 10 cm and 5 cm respectively. If a parallel beam of light falling on lens

L_{1}

, emerges finally through

L_{3}

as a convergent beam such that it converges at the focus of

L_{3}

. Distance between

L_{1} a n d L_{2}

Q. Consider three converging lenses

L_{1}, L_{2}

L_{3}

having identical geometrical construction. The refractive indices of

L_{1}

L_{2}

μ_{1}

μ_{2}

respectively. The upper half of the lens

L_{3}

has refractive index

μ_{1}

and the lower half has

μ_{2}

as shown in the figure. A point object O has an image at

O_{1}

L_{1}

O_{2}

L_{2}

placed in the same position. If

L_{3}

is placed at the same place:

Q. Consider three converging lenses

L_{1}

L_{2}

L_{3}

having identical geometrical construction. The refractive index of

L_{1}

L_{2}

μ_{1}

μ_{2}

respectively. The upper half of the lens

L_{3}

has a refractive index

μ_{1}

and the lower half has

μ_{2}

. A point O is imaged at

O_{1}

L_{1}

O_{2}

L_{2}

placed in same position. If

L_{3}

is placed at same place,

The representation of $l_{1} parallel to l_{2}$ and $l_{3} perpendicular to l_{2}$ is respectively,

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Thin Lenses: Extended Objects

PHYSICS

Watch in App

explore_more_icon

Explore more

Image in Thin Lens by Ray Tracing

Standard XII Physics

Join BYJU'S Learning Program

CrossIcon