Ray Optics and Optical Instruments

A small telescope has an objective of focal length 140 cm and an eye piece of focal length 5.0 cm. The magnifying power of telescope for viewing a distant object is:

[NEET 2024]

Given below are two statements :
Statement I: Image formation needs regular reflection and/or refraction.
Statement II: The variety in colour of objects we see around us is due to the constituent colours of the light incident on them.
In the light of the above statements, choose the most appropriate answer from the options given below:

[Re-NEET 2024]

In a concave lens, a ray of light emanating from the object parallel to the principal axis of the lens, after refraction :

A short straight object of height \(100 \mathrm{~cm}\) lies before the central axis of a spherical mirror whose focal length has absolute value \(|f|=40 \mathrm{~cm}\). The image of object produced by the mirror is of height \(25 \mathrm{~cm}\) and has the same orientation of the object. One may conclude from the information:

An ice cube has a bubble inside. When viewed from one side the apparent distance of the bubble is \(12 \mathrm{~cm}\). when viewed from the opposite side, the apparent distance of the bubble is observed as \(4 \mathrm{~cm}\). If the side of the ice cube is \(24 \mathrm{~cm}\), the refractive index of the ice cube is;

A prism of refractive index \(\mu\) and angle of prism \(A\) is placed in the position of minimum angle of deviation. If minimum angle of deviation is also \(A\), then in terms of refractive index value of \(A\) is:

The magnifying power of a telescope with tube length \( 60 \mathrm{~cm} \) is 5 . What is the focal length of its eye piece ?

[JEE Main 2020, 8 Jan (Shift 1)]

A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since:

A person has been using spectacles of power -1.0 diopter for distant vision and a separate reading glass of power 2.0 diopters. What is the least distance of distinct vision for this person:

Two thin lenses are of same focal lengths (f), but one is convex and the other one is concave. When they are placed in contact with each other, the equivalent focal length of the combination will be :

[NEET 2023]

An object is placed beyond the centre of curvature \(C\) of the given concave mirror. If the distance of the object is \(d_1\) from \(C\) and the distance of the image formed is \(d_2\) from \(C\), the radius of curvature of this mirror is :

A microscope is focused on an object at the bottom of a bucket. If liquid with refractive index \(\frac{5}{3}\) is poured inside the bucket, then microscope has to be raised by \(30 \mathrm{~cm}\) to focus the object again. The height of the liquid in the bucket is:

A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since:

[NEET 2021]

The thickness at the centre of a plano- convex lens is \(3 \mathrm{~mm}\) and the diameter is \(6 \mathrm{~cm}\). If the speed of light in the material of the lens is \(2 \times 10^8 \mathrm{~ms}^{-1}\). The focal length of the lens is