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

In an astronomical telescope in normal adjustment,a straight black line of length $L$ is drawn on the inside part of the objective lens. The eyepiece forms a real image of this line. The length of this image is $I$. The magnification of the telescope is

Magnification produced by an astronomical telescope for normal adjustment is $10$ and the length of the telescope is $1.1 \, m$. The magnification when the image is formed at the least distance of distinct vision $(D = 25 \, cm)$ is

For an astronomical telescope,the focal length of the objective lens is $f_{0}$ and the eyepiece lens is $f_{e}$. Then the tube length of the telescope is . . . . . . .

$A$ telescope has an objective of focal length $100 \ cm$ and an eyepiece of focal length $5 \ cm$. The least distance of distinct vision is $25 \ cm$. The telescope is focused for distinct vision on a scale $3 \ m$ away from the objective. The magnification produced is . . . . . .

There are four convex lenses $L_{1}, L_{2}, L_{3}$ and $L_{4}$ with focal lengths $2 \ cm, 4 \ cm, 6 \ cm$ and $8 \ cm$ respectively. Two of these lenses form a telescope of length $10 \ cm$ and magnifying power $4$. The objective and eye lenses are respectively:

Vedclass Test Series

Exam Paper Generator

Online Exam Module