Question

Assertion : The resolving power of a telescope is more if the diameter of the objective lens is more.
Reason : Objective lens of large diameter collects more light

• A. If both Assertion and Reason are true and Reason is the correct explanation of Assertion
• B. If the Assertion and Reason are true but Reason is not correct explanation of Assertion
• C. If Assertion is true but, Reason is false
• D. If Assertion is false but, Reason is true

Answer 1

Answer: (A)

Resolving power of telescope $=\frac{a}{1.22} \lambda$
where, $a$ is the diameter of objective lens and $\lambda$ is the wavelength of light used. It is obvious that on increasing a more light is collected by objective lens and so, the image formed is more bright. Thus, resolving power of telescope increases.