CBSE Class 12 Physics Competency-Based Questions With Answer Key 2024-25: Chapter 8 Optics FREE PDF Download

CBSE 2024-25 Competency-Based Questions With Answers: The Central Baord of Secondary Education has officially released the practice question paper for the academic year 2024-25, for the classes 10th  and 12th. Competency-focused questions can be helpful for students to secure good marks while referring and practicing them. It will help students to get familiar with the style and format of questions which are expected to appear in the final examinations.

The questions are designied chapter-wise for all the major subject of class 12th. In this article you will find specifically for Class 12 Physics Chapter 8  Optics, the CBSE Board has given the practice question paper for students to understand and up skill there preparation for 2025 examination. At the end of this article free PDF has been attached for the students to access and download. 

CBSE Class 12 Physics Chapter 8 Competency-Based Questions

Question 1:  An object is moved towards a concave mirror at a constant speed, from infinity  to  its  focus.  Which  of  the  following  statements  correctly describes the  corresponding motion in the image formed by the concave mirror? 

1. The image moves slower initially and faster later on, away from the mirror.  
2. The image moves faster initially and slower later on, towards the mirror.  
3. The image moves at a constant speed, faster than the object, away from the  mirror.  
4. The image moves at a constant speed, slower than the object, towards the  mirror. 

Question 2:  Read  the  statements  given  here  carefully.  Each  statement  is  in  reference  to spherical mirrors. Here u, v and f denote the object distance, the image distance and the focal length of the spherical mirror respectively. 

1. A graph plotted between u and v is a hyperbola and when u = f, v = Infinity. 
2. A graph plotted between u and v is a straight line and when u = Infinity, v = f. 
3. A graph plotted between (1/u) and (1/v) is a straight line with an intercept of each axis as (1/f). 
4. A graph plotted between (1/u) and (1/v) is a hyperbola with an intercept of each axis as f. 

Select the correct option. 

1. Statements I and III are correct 
2. Statements II and IV are correct 
3. Statements I and II are correct 
4. Statements III and VI are correct

Question 3: Read the following statements carefully: 

1. A drop of an oil in water or in a glass, both behave as convergent lens. 
2. A water drop in air and a glass sphere in water, both behave as convergent ens. 
3. III. An  air  bubble  in  water  and  a  water  bubble  in  glass,  both  behave  as  a divergent lens. 
4. A frozen ice crystal inside a glass sphere and a bromine liquid drop inside a glass sphere, behave as divergent lens. 

[Reference  values  of  refractive  indices  of  common  substances:  Air  =  1.001; Water = 1.33; ice = 1.31; Glass = 1.51; Oil = 1.4; Bromine = 1.66]  Select the correct option. 

1. Statements I and II are correct. 
2. Statements I and III are correct. 
3. Statements II and III are correct. 
4. Statements II and IV are correct. 

Question 4: An incident light ray falls on a glass prism at an angle of 60o and emerges with an angle of 30o with its initial incident direction. If the angle of the prism is 30o, then which of the following is an incorrect statement? 

1. Refractive index of the prism is √3. 
2. The light undergoes minimum deviation through the prism (i.e., r1 = r2). 
3. The emergent ray is perpendicular to the face from which it emerges. 
4. Angle of refraction r1 at the incident face is same as angle of the prism. 

Question 5:  Which of the following actions will lead to an increase in the magnifying power of an astronomical telescope? 

1. Increase in the length of the telescope tube. 
2. Interchange the objective and the eyepiece of the telescope. 
3. A small piece of paper on the objective of the telescope pointed towards the moon. 
4. Increase in the focal length of the objective and decrease in the focal length of the eye piece. 

Question 6:  In a glass prism of refractive index n, identify the condition for which an incident light emerges out of the prism with a non‐zero deviation. 

1. Angle of prism is zero 
2. B  Angle of incidence is equal to angle of emergence 
3. The n of the material of the prism is same as its surroundings 
4. Sum of angle of incidence and angle of emergence is equal to angle of prism 

Question 7: Study the data related to refractive index and critical angle as given here. 

Identify an INCORRECT conclusion. 

1. Lesser is the value of n, greater is the critical angle. 
2. Greater is the wavelength of the incident light, greater is the corresponding critical angle in a given pair of media. 
3. For  given  beam  of  incident  light  containing  all  angles  of  incidences, maximum total internal reflection is observed at glass‐water interface. 
4. Incident light with angle of incidence equal  to 50oin  the denser medium will  be  total  internally  reflected  in  all  the  above media  except  on  glass‐ water interface. 

Question 8:  A real image of size p times the size of an object is formed by a concave mirror 

of focal length f. What is the object distance from the mirror? 

1. (p+1)*f/p 
2. (p‐1)*f/p 
3. p*f/(p+1) 
4. p*f/(p‐1) 

Question 9: Two superimposing waves are of amplitudes a₁ and a₂ and intensities are I₁ and I₂ respectively. If the ratio I₁:I₂ is 1:16, what will be the ratio of their maximum to minimum intensities upon super‐imposition? 

1.   1/4 
2.   4/1 
3.   25/9 
4.   9/25 

Question 10:  Two waves from a pair of coherent sources strike the screen at a point. For which  of  the  following cases will  the intensity of  superimposed waves be maximum  and  hence  resulting  in  constructive  interference  at  the  given  point  of  observation? 

1. Path difference = 3λ/2; 4λ/2 & Phase difference = 5π 
2. Path difference = 4λ/2 & Phase difference = 0,+5π 
3. Path difference = 3λ; 3λ/2 & Phase difference = ‐2π, 5π 
4. Path difference = 3λ; 4λ/2 & Phase difference = 0, ‐2π 

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To access all the practice question of Physics Chapter 8 Optics, the complete FREE PDFs are attached here. Click on the 'Download PDF' to get the PDF

Why Comptency Based Questions are Important ? 

Competency based questions are important because they help students to understandhow well they can prepare for the examinations. By practicing these question, students gain confidence and strength for the exam they are preparing. It encourages students to reflect on their achievements and understand their strength and weaknesses and also the area of improvements. 

Tips To Prepare For Board Exam 

Here are some tips which will help you to prepare for board exams: 

• Create a Study Plan: Make a study plan before exam will definitely help students. They can break the syllabus into sections and prepare for examinations. 
• Understand the Syllabus: Make sure you are familiar with the syllabus and topics which will be asked in your examinations.  
• Use Quality Study Materials: With NCERT or prescribed textbooks use additional reference books and guides for  ore and better understanding. 
• Practice Past Papers: Practice previous year sample papers just to get familiar withhow the questions will be asked and what will be the exam pattern. 
• Focus on Conceptual Understanding: Understand the concepts thoroughly rather than just memorising facts.
• Regular Revision: Regularly revise what you've studied to brushup your memory and make shorts notes for quick revision

By following these tips, you can improve your preparation for board exams and increase your chances of achieving your desired results.