Single Choice

At Kavalur in India, the astronomers using a telescope whose objective had a diameter of one meter started using a telescope of diameter $$2.54\ m$$. This resulted in

AThe increase in the resolving power by $$2.54$$ times for the same $$\lambda$$
Correct Answer
BThe increase in the limiting angle by $$2.54$$ times for the same $$\lambda$$
CDecrease in resolving power
DNo effect on the limiting angle

Solution

The resolving power of a telescope is given by,
$$R_p=\dfrac{D}{1.22\times \lambda}$$ where, $$D$$ is the diameter of the objective lens and $$\lambda $$ is wavelength of the light.
Hence, we can conclude that, $$R_p \propto D$$.
$$\therefore \dfrac{R_{p_1}}{R_{p_2}}=\dfrac{D_1}{D_2}=\dfrac{1}{2.54}$$
or, $$R_{p_2}=2.54 \times R_{p_1}$$
Hence, option (A) is the correct answer.


SIMILAR QUESTIONS

Optics

An astronomical telescope has an angular magnification of magnitude $$5$$ for distant object. The separation between the objective and the eye piece is $$36\ cm$$and final image is formed at infinity. The focal length of the objective and focal length of eye-piece respectively are:

Optics

The large aperture of telescope are used for

Optics

The minimum magnifying power of telescope is $$M$$. If the focal length of its eye lens is halved, the magnifying power will become:-

Optics

A telescope using light having wavelength $$5000A^o$$ and using lenses of focal $$2.5$$ and $$30cm$$. If the diameter of the aperture of the objective is $$10cm$$, then the resolving limit and magnifying power of the telescope is respectively

Optics

If the telescope is reversed i.e. seen from the objective side

Optics

In an astronomical telescope, the focal lengths of two lenses are $$180\ cm$$ and $$6\ cm$$ respectively. In normal adjustment, the magnifying power will be

Optics

All of the following statements are correct except

Optics

When diameter of the aperture of the objective of an astronomical telescope if increased, its

Optics

The length of a telescope is $$36\ cm$$. The focal lengths of its lenses can be

Optics

The diameter of objective of a telescope is $$1\ m$$. Its resolving limit for the light of wave length $$4538\ A^o$$, will be

Contact Details