MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Laws of Reflection

For a telesco...

Question

For a telescope, the focal lengths of two lenses are 30 cm and 10 cm. One acts as objective and the other as eye-piece. The length of the telescope is

A

40 cm

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

B

3 cm

No worries! We‘ve got your back. Try BYJU‘S free classes today!

C

200 cm

No worries! We‘ve got your back. Try BYJU‘S free classes today!

D

30 cm

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is A 40 cm
focal length of objective lens

$f_{o} = 30 c m$

focal length of eyepiece lens

$f_{e} = 10 c m$
The length of lens

$L = f_{o} + f_{e}$

$L = 30 + 10 = 40 c m$

Option A is correct.

Suggest Corrections

thumbs-up

0

Similar questions

Q. A small laboratory telescope has an objective lens of focal, length

140 c m

and an eye-piece of focal length

6 c m

. Then, separation between the objective and eye-piece is :

Q. A small telescope has an objective lens of focal length 144 cm and an eye piece of focal length 6.0 cm. What is the separation between the objective and the eye piece then?

Q. A telescope has objective and eye-piece of focal lengths 200 cm and 2 cm respectively. The magnifying power of the telescope for normal vision is

Q. The objective of a terrestrial telescope has focal length of 120 cm and diameter 5 cm. The focal length of the eye piece is 2 cm. The magnifying power of telescope for distant object is :

Q. A telescope has a objective of focal length

50 c m

and an eye-piece of focal length

5 c m

. The least distance of distinct vision is

25 c m

. The telescope is focused for distinct vision on a scale of

200 c m

away. The separation between the objective and the eye-piece is

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Ray Diagrams of Spherical Mirrors

PHYSICS

Watch in App

explore_more_icon

Explore more

Laws of Reflection

Standard VIII Physics

Join BYJU'S Learning Program

CrossIcon