EASY
JEE Main
IMPORTANT
Earn 100

A simple microscope is rated 5x for a normal relaxed eye. What will be its magnifying power for a relaxed farsighted eye whose near point is 40 cm?

Important Questions on Optical Instruments

HARD
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 19 - Optical Instruments>EXERCISES>Q 6
Find the maximum magnifying power of a compound microscope having a 25 D lens as the objective, a 5 D lens as the eyepiece and the separation 30 cm between the two lenses. The least distance for clear vision is 25 cm.
HARD
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 19 - Optical Instruments>EXERCISES>Q 7
The separation between the objective and the eyepiece of a compound microscope can be adjusted between 9.8 cm to 11.8 cm. If the focal lengths of the objective and the eyepiece are 1.0 cm and  6 cm, respectively, find the range of the magnifying power if the image is always needed at 24 cm from the eye.
HARD
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 19 - Optical Instruments>EXERCISES>Q 8
An eye can distinguish between two points of an object if they are separated by more than 0.2 mm when the object is placed at 25 cm from the eye. The object is now seen by a compound microscope having a 20 D objective and 10 D eyepiece separated by a distance of 20 cm. The final image is formed at 20 cm from the eye. What is the minimum separation between two points of the object which can now be distinguished?
EASY
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 19 - Optical Instruments>EXERCISES>Q 9
A compound microscope has a magnifying power of 100 when the image is formed at infinity. The objective has a focal length of 0.5 cm and the tube length is 6.5 cm. Find the focal length of the eyepiece.
EASY
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 19 - Optical Instruments>EXERCISES>Q 10
A compound microscope consists of an objective of focal length 1 cm and an eyepiece of focal length 5 cm. An object is placed at a distance of 0.5 cm from the objective. What should be the separation between the lenses so that the microscope projects an inverted real image of the object on a screen 30 cm behind the eyepiece?
HARD
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 19 - Optical Instruments>EXERCISES>Q 11

An optical instrument used for angular magnification has a 25 D objective and 20 D eyepiece. The tube length is 25 cm when the eye is least strained.

(a) Whether it is a microscope or a telescope?

(b) What is the angular magnification produced?

EASY
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 19 - Optical Instruments>EXERCISES>Q 12
An astronomical telescope is to be designed to have a magnifying power of 50 in normal adjustment. If the length of the tube is 102 cm, find the powers of the objective and the eyepiece.
EASY
JEE Main
IMPORTANT
CONCEPTS OF PHYSICS [VOLUME 1]>Chapter 19 - Optical Instruments>EXERCISES>Q 13
The eyepiece of an astronomical telescope has a focal length of 10 cm. The telescope is focussed for normal vision of distant objects when the tube length is 1.0 m. Find the focal length of the objective and the magnifying power of the telescope.