wiz-icon
MyQuestionIcon
MyQuestionIcon
14
You visited us 14 times! Enjoying our articles? Unlock Full Access!
Question

The magnifying power of a telescope with a tube length of 60cm is 5. What is the focal length of its eyepiece?


A

10cm

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

20cm

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

30cm

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

40cm

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

The correct option is A

10cm


Step 1. Given data:

The magnifying power of the telescope m=5.

The length of the tube=60cm.

Step 2. Formula used:

m=fefo where the focal length of the eyepiece lens is fe, and the focal length of the objective lens is fo

The total length of the telescope=fe+fo

Step 3. Calculating the focal length of the eyepiece,

m=fofe=5fo=5fe

And,

fe+fo=60fe+5fe=606fe=60fe=606=10

Thus the focal length of the eyepiece is10cm

Hence, option A is the correct answer.


flag
Suggest Corrections
thumbs-up
9
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Telescope
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon