A simple telescope consisting of an objective | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) The angular magnification $M$ of a telescope in normal adjustment (where parallel rays emerge from the eye-lens) is given by the ratio of the foca

Vedclass · Accepted Answer

$24$

Vedclass · Answer

(B) The angular magnification $M$ of a telescope in normal adjustment (where parallel rays emerge from the eye-lens) is given by the ratio of the focal length of the objective $(f_o)$ to the focal length of the eye-lens $(f_e)$: $M = \frac{f_o}{f_e}$ Also,the angular magnification is defined as the ratio of the angle subtended by the image at the eye $(\beta)$ to the angle subtended by the object at the objective $(\alpha)$: $M = \frac{\beta}{\alpha}$ Given: $f_o = 60\,cm$ $f_e = 5\,cm$ $\alpha = 2^o$ Equating the two expressions for magnification: $\frac{f_o}{f_e} = \frac{\beta}{\alpha}$ $\frac{60}{5} = \frac{\beta}{2}$ $12 = \frac{\beta}{2}$ $\beta = 12 	imes 2 = 24^o$ Therefore,the angular width of the image is $24^o$.

Similar Questions

$A$ Galilean telescope has an objective and an eyepiece of focal lengths $200 \, cm$ and $2 \, cm$ respectively. The magnifying power of the telescope for normal vision is

The magnifying power of a refracting type of astronomical telescope is $m$. If the focal length of the eyepiece is doubled,then the magnifying power will become:

In normal adjustment,for a refracting telescope,the distance between the objective and the eyepiece is $30\,cm$. The focal length of the objective,when the angular magnification of the telescope is $2$,will be $.....\,cm$.

In an astronomical telescope,the focal length of the objective lens is $100 \, cm$ and of the eyepiece is $2 \, cm$. The magnifying power of the telescope for the normal eye is:

The magnifying power of a telescope is $9.$ When it is adjusted for parallel rays,the distance between the objective and eyepiece is $20\; cm.$ The focal lengths of the lenses are:

Vedclass Test Series

Exam Paper Generator

Online Exam Module