Answer the following.
What is meant by a thin prism?
No answer yet.
Ray Optics and Optical Instruments - ISC Class 12 Physics Questions with Answers, Page 4
122 past-paper questions on Ray Optics and Optical Instruments from ISC Class 12 Physics papers (2027-2018), newest first, in full. Questions 61-80 are on this page, 20 to a page. Tap "Show answer" under a question to see its answer.
Nothing matches. Try fewer letters.
Answer the following.
What error do you observe in the readings of Student 1?
No answer yet.
Answer the following.
What is the focal length of the final combination?
No answer yet.
Solve the following.
For a science project, two fish tanks with lids were constructed as shown in the figure. Tank X has a lid with a convex shape, while Tank Y has a lid with a concave shape and no space between the lid and the liquid. Both tanks have the same height of 24 cm and are made of glass with a refractive index of 1.5. The radius of curvature of both lids is 40 cm. Which tank appears to have the fish positioned higher? Support the answer with necessary calculations.
No answer yet.
Answer the following.
A convex lens having small focal length is to be used as a magnifying glass (simple microscope) to obtain an image of a small diamond. If the image lies at least distance of distinct vision ($D$):
(i)[1.5]
Where will you keep the diamond to obtain its image at $D$?
(ii)[1.5]
State any two characteristics of the image formed by the magnifying glass.
No answer yet.
Study the Assertion and Reason and choose the correct option.
Assertion: An astronomical telescope has an objective lens having large focal length.
Reason: Magnifying power of an astronomical telescope varies directly with focal length of the objective lens.
- (a)Both Assertion and Reason are true and Reason is the correct explanation for Assertion.
- (b)Both Assertion and Reason are true but Reason is not the correct explanation for Assertion.
- (c)Assertion is false and Reason is true.
- (d)Both Assertion and Reason are false.
No answer yet.
Answer the following.
The focal length of a double convex lens is equal to the radius of curvature of either surface. What is the refractive index of its material?
No answer yet.
Answer the following.
State any one difference between a primary rainbow and a secondary rainbow.
No answer yet.
Answer the following.
Which material is used to make this glass slab?
No answer yet.
Solve the following.
Figure 10 below shows a ray of monochromatic light incident normally on first surface AB of an equilateral glass prism ABC, whose adjacent surface AC is covered with a transparent liquid. If the emergent ray grazes the surface AC, calculate refractive index of the liquid.
(Refractive index of glass = 1.5)
No answer yet.
Answer the following.
EXAMINER: Write the relation between the optical power (P) and the focal length (f) of the convex lens.
STUDENT writes P = 2f.
No answer yet.
Solve the following.
Figure 5 below shows a ray of monochromatic light LM incident on the first surface AB of a regular (equilateral) glass prism ABC. The emergent ray grazes the adjacent surface AC. Calculate the angle of incidence. (Refractive Index of glass = 1.5)
No answer yet.
Choose the correct option.
When a ray of white light is incident obliquely on the first surface of a prism, then
- (a)red colour is deviated most.
- (b)green colour is deviated most.
- (c)yellow colour is deviated most.
- (d)violet colour is deviated most.
No answer yet.
Answer the following.
There are two types of optical instruments: Microscopes and Telescopes. Microscopes are used to magnify very tiny objects whereas telescopes are used to study distant objects. Both of them deploy convex lenses. In his telescope, Newton used a large parabolic mirror to collect light from the stars and reduce aberrations.
(i)[1.0]
Rohit observed the launch of Chandrayan 3 with the help of an optical instrument. Name the instrument used by him.
(ii)[1.0]
State any one advantage of a reflecting telescope over a refracting telescope.
(iii)[1.0]
Which instrument is used to study the structure of a virus?
(iv)[1.0]
What is the ability of an optical instrument to form enlarged images called?
(v)[1.0]
What is the difference between a compound microscope and an astronomical telescope (refracting type), as far as their lenses are concerned?
No answer yet.
Answer the following.
EXAMINER: Plot a graph of (1/v) against (1/u).
STUDENT takes (1/v) on Y axis and (1/u) on X axis.
No answer yet.
Answer the following.
EXAMINER: Image formed by the lens is magnified. Reduce the size of the image.
STUDENT moves the lens towards the object pin.
No answer yet.
Choose the correct option.
If an object is placed at a distance of $10\text{ cm}$ in front of a concave mirror of focal length $20\text{ cm}$, the image formed will be:
- (a)real and $20\text{ cm}$ in front of the mirror.
- (b)real and $6\cdot67\text{ cm}$ in front of the mirror.
- (c)virtual and $20\text{ cm}$ behind the mirror.
- (d)virtual and $6\cdot67\text{ cm}$ behind the mirror.
No answer yet.
Answer the following.
There are two types of lenses: Converging lenses and Diverging lenses, depending on whether they converge or diverge an incident beam of light. They are also called convex or concave lenses. Lenses are usually made of glass. Convex lenses are more popular as they form a real image of an object. They are widely used in our daily life, for instance, in microscopes, telescopes, projectors, cameras, spectacles etc. Microscopes are used to view small and nearby objects whereas telescopes are used to see distant objects.
(i)[1.0]
State any one factor on which focal length of a lens depends.
(ii)[1.0]
Give an example where a convex lens behaves like a diverging lens.
(iii)[1.0]
What type of lens is used in a camera?
(iv)[1.0]
Write an expression for magnifying power of a compound microscope when its final image lies at the least distance of distinct vision ($D$).
(v)[1.0]
State any one difference between a reflecting telescope and a refracting telescope.
No answer yet.
Derive the following.
Obtain an expression for refraction at a single convex spherical surface i.e., the relation between $\mu_1$ (rarer medium), $\mu_2$ (denser medium), object distance $u$, image distance $v$ and the radius of curvature $R$.
No answer yet.
Derive the following.
Derive Lens Maker’s formula.
Given: A thin convex lens bounded by spherical surfaces of radii of curvature $R_1$ and $R_2$
To show: $\frac{1}{f} = (n - 1)\left(\frac{1}{R_1} - \frac{1}{R_2}\right)$
No answer yet.