Question

What are the limitations in increasing the magnifying powers of 

(i) simple microscope 

(ii) compound microscope 

(iii) astronomical telescope?

Answer 1

i. In case of simple microscope

Thus, the limitation in increasing the magnifying power is determined by the value of focal length and the closeness with which the lens can be held near the eye.

ii. In case of compound microscope,

Thus, in order to increase m₀, we need to decrease u₀. Thereby, the object comes closer and closer to the focus of the objective. This increases v₀ and hence length of the microscope. Therefore, mQ can be increased only within the limitation of length of the microscope.

iii. In case of telescopes,

M = f₀/f_e 

Where f₀ = focal length of the objective f_e = focal length of the eye-piece

Length of the telescope for normal adjustment is, L = f₀ + f_e.

Thus, magnifying power of telescope can be increased only within the limitations of length of the telescope.