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In an internal focusing type of telescope, the lens provided is

In an internal focusing type of telescope, the lens provided is Correct Answer Concave

In the internal focusing telescope, the objective and eye-piece do not move when the focusing screw is turned. Here, a double concave lens is fitted with a rack and pinion arrangement between the eye-piece and the objective. This lens moves to and fro when the focusing screw is turned and a real image is formed on the plane of cross-hairs.

Related Questions

Which statement is correct about telescope: a) The focal length of the objective lens is more than the eyepiece. b) The focal length of the eyepiece is more than the objective lens. c) The aperture of the objective lens is more than the eyepiece. d) The aperture of the eyepiece is more than the objective lens.
A concave lens provided in telescope between the object lens and eye piece to eliminate the additive constant (f + d) from the Tachernetric distance equation is known as an . . . . . . . . lens.
If altitude bubble is provided both on index frame as well as on telescope of a theodolite, then the instrument is levelled with reference to
i) altitude bubble on index frame
ii) altitude bubble on index frame if it is to be used as a level
iii) altitude bubble on telescope
iv) altitude bubble on telescope if it is to be used as a level
The correct answer is
 Which of the following statements is/are true of the human eye lens? Choose the correct answer from the code given below:  (i) It is a convex lens (ii) It is a concave lens (iii) It is a convex lens of variable focal length (iv) It forms a real and inverted image of a distant object at the retina
Given below are four statements- (p) The second principal focus of a lens is the position of the object, real or virtual whose image is at infinity. (q) The second principal focus of a lens is the position of the image, real or virtual whose object is at infinity. (r) The first principal focus of a lens is the position of the object, real or virtual whose image is at infinity. (s) The first principal focus of a lens is the position of the image, real or virtual whose object is at infinity.  Examine the above statements and find which among then are correct. 
Accommodation is a process in the eye where
1. Ciliary muscles attached to the lens
flatten it for distant objects
2. Ciliary muscles attached to the lens thicken for closer objects
3. Ciliary muscles flatten the lens for closer objects
4. Ciliary muscles thicken the lens for distant objects
Select the correct answer from the options given below:
In internal focussing telescope, the additional concave lens inside the short tube can be moved between the object lens and diaphragm by means of . . . . . . . . arrangement.
In an internal focussing type of telescope, the lens provided is
In an observation with a telescope, having aperture of lens D, if the wavelength of the light is tripled then the resolving power of telescope will-
The focal length of the objective lens of a telescope is 50 cm. If the magnification of the telescope is 25, then the focal length of the eyepiece is