Question

In which of the following instruments is the final image erect?

• A. Simple microscope
• B. Galilean telescope
• C. Astronomical telescope
• D. Both (A) and (C)

Answer 1

The correct option is D

Both (A) and (C)

The explanation of the correct option

In case of option D

The image formed by a Simple microscope

1. The enlarged image of an object is examined with a simple microscope.
2. It is mostly dependent on the use of a light microscope. A virtual, erect, and enlarged picture is produced when an object is put inside the focal length of a convex lens.
3. A basic microscope is made with a biconvex lens. A reading glass or magnifying glass with a convex lens is the most common and commonly used type of convex lens.
4. Compound microscopes are now utilized to acquire better magnification by combining two or more convex lenses.

The image formed by the Galilean telescope

1. The focal length of the objective lens of a Galilean telescope is equal to the difference between the length of the two lenses and the focal length of the eye-piece,$f_o=L+f_e[where{f}_o,f_e=focallengthsofobjectivelensandeye-length,L=dis\tan ce]$
2. To calculate the focal length of the eyepiece, substitute the values of L and the focal length of the objective lens.
3. Magnification is defined as the negative ratio of the focal length of the objective lens to the focal length of the eyepiece.

The explanation of the incorrect option

In case of option A

The image formed by the Simple microscope is erect. But the option A is not the most appropriate option among all the four options.

In case of option B

The image formed by the Galilean microscope is erect. But the option B is not the most appropriate option among all the four options.

In case of option C

The image formed by the Astronomical telescope

1. The objective lens concentrates light rays to create a true image of a distant object.
2. This image is created in the same plane as the objective lens's principal focus when light rays cross each other after traveling through the lens.
3. The eyepiece magnifies this genuine image for the observer gazing through the telescope.
4. Because the rays emanating from the eyepiece appear to be coming from behind the eyepiece, this magnified representation of the object is called a virtual image.
5. In comparison to the distant object, the virtual image is inverted

.

Hence, option D is the correct answer.