NCERT Solutions for Class 12 Physics Chapter 10 - Wave Optics - PDF Download
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NCERT Solutions for Wave Optics Class 12 are now available for you, who want to get the best preparation for the exam. All the questions from this chapter 10 along with the extra questions are solved. Expert Physics teachers solved these questions in a very simple language. To secure more marks in Physics, Download NCERT Solutions Class 12 Physics Wave Optics PDF which is available in the free PDF format.
In chapter 10 wave optics, you will learn about Huygens' principle, refraction and reflection of plane waves, coherent and incoherent waves and each topic is explained with experiment and examples. After completing the topics then you will get exercise to solve.
Topics Covered in Class 12 Physics Chapter 10 Wave Optics
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Section Number |
Topic |
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10.1 |
Introduction |
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10.2 |
Huygens’ Principle |
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10.3 |
Refraction and Reflection of Plane Waves Using Huygens Principle |
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10.3.1 |
Refraction of a Plane Wave |
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10.3.2 |
Refraction at a Rarer Medium |
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10.3.3 |
Reflection of a Plane Wave by a Plane Surface |
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10.4 |
Coherent and Incoherent Addition of Waves |
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10.5 |
Interference of Light Waves and Young’s Experiment |
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10.6 |
Diffraction |
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10.6.1 |
The Single Slit |
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10.6.2 |
Seeing the Single Slit Diffraction Pattern |
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10.6.3 |
Resolving Power of Optical Instruments |
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10.6.4 |
The Validity of Ray Optics |
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10.7 |
Polarisation |
Huygens’ Principle
When we throw a small stone on a calm pool of water, waves spread out from the point of impact. Each point on the surface starts oscillating with time. At any point of time, a photograph of the surface would show circular rings on which the disturbance is maximum. It is very clear, all points on such a circle are oscillating in phase because they all are at the same distance from the source. Such a locus of points, which oscillate in phase, is known as wavefront. Huygens' principle is also known as Huygens-Fresnel principle, a statement that all points of a wave front of sound in a transmitting medium or of light in a vacuum or transparent medium may be regarded as new sources of wavelets that expand in every direction at a rate depending on their velocities.
Refraction and Reflection of Plane Waves Using Huygens Principle
Huygens's principle applied to a plane wave front travelling from one medium to another medium, where the speed of the wave is less. Huygens principle says that every point on a wavefront is in itself the source of spherical wavelets.
Refraction of a Plane Wave
The bending of light waves of light waves is called refraction. The amount of refraction depends on two things: one is the change in the speed of light and another one is the angle at which the waves are bending. Snell's law states that the relationship between angles of incidence and refraction, and the refractive index of each medium.
Refraction at a Rarer Medium
When a wave travels from denser to rarer medium it bends away from the normal and angle of refraction is always greater than angle of incident. When a wave travels from rarer to denser medium the refracted ray bends towards the normal and the angle of refraction is less than the angle of incidence.
Reflection of a Plane Wave by a Plane Surface
As per the Snell's law the ratio of sine of angle of incidence to the sine of angle of refraction is equal to the ratio of refractive index of second medium to the first medium. Huygen's principle states that each point on a wavefront is a source of secondary waves, which add up to later wavefronts.
Coherent and Incoherent Addition of Waves
Coherent waves are those waves which have the same frequency and zero or constant phase difference. Incoherent waves have random phase differences and frequencies. Addition of waves deal with the interference patterns that are created by the superposition of two waves.
Interference of Light Waves and Young’s Experiment
Young's double slit experiment uses two coherent sources of light s1 and s2 which are placed at a small distance apart. Usually, only those magnitudes greater than the wavelength of light are used. Young's double slit experiment helped in understanding the wave theory of light.
Diffraction
Diffraction is the slight changes in direction of light as it passes around the edge of an object. The amount of bending of light depends on the relative size of the wavelength of light to the size of the opening. If the opening is much larger than the light's wavelength, the bending will be almost unseen.
Polarisation
Polarization or polarisation is a property of transverse waves which specifies the geometrical orientation of the oscillations.Transverse wave is the direction of the oscillation is perpendicular to the direction of motion of the wave.
Benefits of NCERT Solutions for Class 12 Physics Chapter 10 Wave Optics -
Some important benefits that you would get with the help of NCERT Solutions of Wave Optics Class 12 are given below
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All of these solutions are written while keeping your exam guidelines in mind.
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NCERT Solution of Wave Optics Class 12th is written in such an easy way that every student can understand it.
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These solutions are available in PDF format and you can download this at any time and access them.
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The given solution is easily accessible offline for future use, so you can easily practice it before the exam.
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Physics Ch 10 Class 12 NCERT Solutions encourages you to develop your answering skills. Students are given point-wise solutions.
Frequently Asked Questions
Find answers to common questions.
What are the most important topics in Class 12 Physics Chapter 10 for board exams?
The most important topics for CBSE board exams are Huygens' Principle (derivation of laws of reflection and refraction), Young's Double Slit Experiment (fringe width formula and numericals), single slit diffraction (condition for minima), and Brewster's Law with Malus' Law. These topics account for the majority of marks in board question papers from the last five years.
How many exercises are in NCERT Class 12 Physics Chapter 10?
Chapter 10 Wave Optics contains 21 questions in the main exercise and several additional exercises. The questions range from short conceptual answers to numerical problems involving fringe width, resolving power, and intensity calculations. All 21 questions plus additional problems are solved in the eSaral NCERT Solutions PDF.
Is Wave Optics important for JEE Main?
Yes. Wave Optics carries approximately 4–8% weightage in JEE Main Physics, with 1–3 questions appearing in most sessions. According to NTA's official analysis, Young's Double Slit Experiment and single slit diffraction are the most frequently tested sub-topics. Polarisation questions (Malus' Law, Brewster's angle) also appear regularly.
What is the fringe width formula in Young's Double Slit Experiment?
Fringe width β = λD/d, where λ is the wavelength of light used, D is the distance between the slits and the screen, and d is the distance between the two slits. Fringe width is the same for all consecutive bright or dark fringes in ideal YDSE conditions. Increasing D or λ increases fringe width; increasing d decreases it.
What is the difference between a wavefront and a wave ray?
A wavefront is the locus of all points in a medium that are oscillating in the same phase at a given instant — it is a surface. A ray is an arrow drawn perpendicular to the wavefront, showing the direction in which the wave energy is travelling. For a point source, wavefronts are spherical and rays point radially outward.