Conceptual Questions for Class 12 Physics Chapter 10 Wave Optics

Here we are providing conceptual questions based on Class 12 Physics Chapter 10 Wave Optics. Go through each and every question for better understanding.

Q.1. What are the reasons to believe that light is a wave motion?

Solution. Light undergoes interference, diffraction and polarization. These phenomena establish that light is a wave motion.

Q.2. Is it necessary that the amplitude be constant over a given wavefront?

Solution. Yes, In a homogeneous medium, the amplitude is constant on a given wavefront.

Q.3. Can two wavefronts cross one another? Give reason.

Solution. No if they intersect, then there will be two rays or two directions of propagation of energy at the point of intersection which is not possible.

Q.4. What happens to the interference pattern if the phase difference between the two sources varies continuously?

Solution. The positions of bright and dark fringes will change rapidly. Such rapid changes cannot be detected by our eyes. A uniform illumination is seen on the screen i.e., interference pattern disappears.

Q.5. Two slits in Young’s double slit experiment are illuminated by two different lamps emitting light of the same wavelength. Will you observe the interference pattern? Justify your answer.

Solution. No. The light waves emitted by two different lamps cannot be coherent. So, the conditions of maxima and minima of intensity will change rapidly on the screen, producing uniform illumination.

Q.6. ‘Two independent monochromatic sources of light cannot produce a sustained interference pattern’. Give reason.

Solution. The phase difference between the light waves originating from two independent monochromatic sources will change rapidly with time. The two sources will not be coherent and, therefore, will not produce a sustained interference pattern.

Q.7. Why should we have a narrow source to produce good interference fringes?

Solution. It is because a broad source is equivalent to a large number of narrow sources lying close to each other. Different pairs of narrow sources will produce their own interference patterns which will overlap each other. So, the fringe system is lost.

Q.8. Why is interference pattern not detected, when the two coherent sources are far apart?

Solution. When the distance d between the two coherent sources is large, the fringe width (β ∝ 1/ d) becomes too small to be detected. The interference pattern cannot be observed.

Q.9. Explain the statement ‘light added to light can produce darkness’.

Solution. When two light waves of equal amplitude meet at a point in opposite phases, the resultant amplitude and hence intensity become zero at that point. That is when light added to light undergoes destructive interference, it produces darkness.

Q.10. What happens to the light energy when light waves interfere destructively at a point?

Solution. Energy gets transferred from the regions of destructive interference to the regions of constructive interference.

Q.11. Why is it comparatively difficult to observe interference in light waves as compared to that in water waves?

Solution. This is because the wavelength of light waves is much smaller than the wavelength of water waves. Consequently, the interference fringes have much smaller width in case of light waves than in water waves.

Q.12. Is there any difference between the colours emerging from a prism and the colours of a soap film seen in sunlight?

Solution. Yes. In the prism, colours are produced due to dispersion of light. The colours of a soap film are due to interference of light.

Importance of conceptual questions for class 12 physics

Conceptual questions are of utmost importance in Class 12 Physics for several reasons. These questions focus on understanding the fundamental principles and concepts rather than just rote memorization of equations and formulas. Here are some reasons why conceptual questions are crucial in Class 12 Physics:

Deep understanding: Conceptual questions require students to grasp the underlying principles and theories behind physical phenomena. This leads to a deeper understanding of the subject, making it easier to apply the knowledge to various problem-solving scenarios.
Critical thinking: When students tackle conceptual questions, they are encouraged to think critically and analytically. These questions often involve complex scenarios that demand logical reasoning and creative thinking to arrive at the right answers.
Problem-solving skills: Conceptual questions challenge students to solve unfamiliar and intricate problems. As a result, their problem-solving skills are honed, preparing them to tackle more advanced scientific challenges in the future.
Application of concepts: By answering conceptual questions, students learn to apply theoretical concepts to practical situations. This bridges the gap between theory and real-world applications, fostering a holistic understanding of Physics.
Better exam preparation: Class 12 board exams and competitive entrance exams often include conceptual questions. Preparing for such questions not only improves performance in exams but also sets a strong foundation for further studies in physics-related fields.
Enhanced retention: Understanding concepts leads to better retention of knowledge. Unlike rote memorization, conceptual understanding stays with students for a long time, making it easier to build on that knowledge in the future.
Encouraging curiosity: Conceptual questions often pique students’ curiosity and encourage them to explore the subject further. This can spark an interest in Physics as a whole, leading to a lifelong passion for the subject.
Formulating connections: Conceptual questions help students make connections between different topics and subfields within Physics. This interconnected knowledge is essential for a comprehensive understanding of the subject.
Learning from mistakes: When students attempt conceptual questions, they may make mistakes. However, these mistakes provide valuable learning opportunities, as they highlight areas that need further clarification and understanding.
Building confidence: Successfully answering conceptual questions gives students a sense of accomplishment and boosts their confidence in their Physics abilities.

Conceptual Questions for Class 12 Physics Chapter 10 Wave Optics

Conceptual Questions for Class 12 Physics Chapter 10 Wave Optics

Importance of conceptual questions for class 12 physics

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