Optical Instruments & the Eye
Given below are two statements: one is labeled as Assertion A and the other is labeled as Reason R.
Assertion A: For a simple microscope, the angular size of the object equals the angular size of the image.
Reason R: Magnification is achieved as the small object can be kept much closer to the eye than 25 cm and hence it subtends a large angle.
In the light of the above statements, choose the most appropriate answer from the options given below:
Show answer and solution
Answer: (c)
- For a simple microscope, the virtual image subtends at the eye the same angle as the object itself (both lie on the same rays through the lens centre), so A is true.
- The lens lets the object be kept much closer than 25 cm while still seen clearly, so it subtends a larger angle than it would at 25 cm; R is true.
- This closeness is exactly why magnification is achieved, so R explains A.
- So the answer is (c).