Question

A simple telescope used to view distant objects has eyepiece and objective lens of focal lengths $f_e$ and $f_0$, respectively. Match Column I with Column II:

Column I		Column II
A	Intensity of light received by lens.	P	Radius of aperture (R).
B	Angular magnification.	Q	Dispersion of lens.
C	Length of telescope.	R	Focal length $f_0,f_e$.
D	Sharpness of image.	S	Spherical aberration.

• A. $(A)\to (P);(B)\to (R);(C)\to (R);(D)\to (P),(S)$
• B. $(A)\to (P);(B)\to (R);(C)\to (R);(D)\to (P),(Q)$
• C. $(A)\to (P);(B)\to (R);(C)\to (R);(D)\to (Q),(S)$
• D. $(A)\to (P);(B)\to (R);(C)\to (R);(D)\to (P),(Q),(S)$

Answer 1

Answer: (D)

$(A)\to (P)$
The intensity of the light received by the lens is given by $l\propto$ Area of aperture
(B) $\to$ (R)
Angular magnification $=\frac{f_0}{f_e}$
$(C)\to (R)$
The length of the telescope is $1=f_0+f_e$.
$(D)\to (P),(Q),(S)$
The concepts and definitions are self-explanatory.