NCERT Solutions for Class 12 Help.html Physics Part Ii Chapter 10 Wave Optics

Wave Optics Here is the CBSE Help.html Chapter 10 for Class 12 students. Summary and detailed explanation of the lesson, including the definitions of difficult words. All of the exercises and questions and answers from the lesson's back end have been completed. NCERT Solutions for Class 12 Help.html Wave Optics Chapter 10 NCERT Solutions for Class 12 Help.html Wave Optics Chapter 10 The following is a summary in Hindi and English for the academic year 2025-26. You can save these solutions to your computer or use the Class 12 Help.html.

Question 1

Wired Faculty App

A small candle, 2.5 cm in size is placed at 27 cm in front of a concave mirror of radius of curvature 36 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image? Describe the nature and size of the image. If the candle is moved closer to the mirror, how would the screen have to be moved?

Solution

Given,

Object size = 2.5 cm

Object distance, u = - 27 cm Radius of curvature, R = 36 cm Focal length, f = \frac{R}{2} = \frac{- 36}{2} = - 18 cm Image distance, \frac{1}{v} = \frac{1}{f} - \frac{1}{u} = - \frac{1}{18} - \frac{1}{- 27} \Rightarrow \frac{1}{v} = \frac{1}{27} - \frac{1}{18} = - \frac{1}{54} i . e ., v = - 54 cm

The negative sign indicates that the image is formed in front of the mirror. Thus, the screen should be placed at a distance of 54 cm in front of the mirror on the same side as that of the object.

Now,
Magnification,

m = \frac{I}{O} = - \frac{v}{u}

∴

\frac{I}{2.5} = \frac{- 54}{- 27} I = - 5 cm

As size of image is (–)ve. So image is inverted and real.

When the candle is moved closer to mirror, the screen would have to be moved farther and farther. However, when the candle is closer than 18 cm from the mirror, the image would be virtual and therefore cannot be collected on the screen.

Sponsor Area

For Daily Free Study Material Join wiredfaculty

WhatsApp Group

Download Android App

Ncert Book Download

NCERT Solutions for Class 12 Help.html Physics Part Ii Chapter 10 Wave Optics

A 4.5 cm needle is placed 12 cm away from a convex mirror of focal length 15 cm. Give the location of the image and the magnification. Describe what happens as the needle is moved farther from the mirror.

Figures (a) and (b) show refraction of a ray in air incident at 60° with the normal to a glass-air and water-air interface, respectively. Predict the angle of refraction in glass when the angle of incidence in water is 45° with the normal to a water-glass interface. [ Fig. 9.34 (c)].

Double-convex lenses are to be manufactured from a glass of refractive index 1.55, with both faces of the same radius of curvature. What is the radius of curvature required if the focal length is to be 20 cm?

A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12 cm from P. At what point does the beam converge if the lens is (a) a convex lens of a focal length 20 cm, and (b) a concave lens of focal length 16 cm?

An object of size 3.0 cm is placed 14 cm in front of a concave lens of focal length 21 cm. Describe the image produced by the lens. What happens if the object is moved further away from the lens?

What is the focal length of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm? Is the system a converging or a diverging lens? Ignore thickness of the lenses.

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Phone Number

Email Address

Loaction