Question

A planet is observed by an astronomical refracting telescope having an objective of focal length $16m$ and an eyepiece of focal length $2cm$. Then,

• A. The distance between the objective and the eyepiece is $16.02m$
• B. The angular magnification of the planet is $-800$
• C. The image of the planet is inverted
• D. The objective is larger than the eyepiece

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A The distance between the objective and the eyepiece is $16.02m$
B The angular magnification of the planet is $-800$
C The image of the planet is inverted
D The objective is larger than the eyepiece

$f_o=16m$ and $f_e=2cm$ i.e, objective is larger than the eyepiece

the distance between them is $f_o+f_e=16+0.02=16.02m$

magnification is $-\frac{f_0}{f_e}=-\frac{16}{0.02}=-800$

the final image is inverted as magnification is negative, hence option $A,B,C,D$ are correct