Question

The resolving power of an astronomical telescope is $0.2$ seconds. If the central half portion of the objective lens is covered, the resolving power will be:-

• A. $0.1sec$
• B. $0.2sec$
• C. $1.0sec$
• D. $0.6sec$

Answer 1

The correct option is A $0.1sec$

As we know,

Resolving power $p=\frac{a}{1.22\lambda }$

so,

$p\propto a$

$\frac{p_1}{p_2}=\frac{a_1}{a_2}$

$\frac{p}{0.2}=\frac{a/2}{a}$

hence $P=0.1$