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

Answer 1

Answer: (D)

$( A ) \rightarrow( P )$
The intensity of the light received by the lens is given by $l\propto$ Area of aperture
(B) $\rightarrow$ (R)
Angular magnification $=\frac{f_{0}}{f_{e}}$
$( C ) \rightarrow( R )$
The length of the telescope is $1=f_{0}+f_{e}$.
$(D) \rightarrow(P),(Q),(S)$
The concepts and definitions are self-explanatory.