An astronomical telescope is to be assembled in a laboratory
PHYSICS · Subjective · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
An astronomical telescope is to be assembled in a laboratory.
(i) Derive an expression for the magnifying power of an astronomical telescope when it is adjusted to form its final image at infinity.
(ii) The objective chosen has a focal length of 120 cm and the eyepiece has a focal length of 3.0 cm. Calculate the magnifying power in the condition stated in part (i).
(iii) The diameter of the objective is 25 cm. Estimate the ratio of its light-gathering power to that of the unaided human eye whose pupil diameter is 5 mm.
(iv) State any two practical advantages that a reflecting telescope of the same aperture would offer over the refracting telescope described above.