To construct an astronomical telescope, the separation between the two converging lenses of focal lengths 100 cm and 10 cm should be
A) 10 cm.
B) 90 cm.
C) 100 cm.
D) 110 cm.

Question

Quizplus · Accepted Answer

The separation between the two lenses in an astronomical telescope, when adjusted for parallel rays (i.e., focused at infinity), is equal to the sum of their focal lengths. Therefore, the separation is 100 cm + 10 cm = 110 cm.

To Construct an Astronomical Telescope, the Separation Between the Two