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 7 Electromagnetic Waves, 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.
Also Read: Electromagnetism: Definition, Key Concepts, Formula and Applications; Download in PDF
CBSE Class 12 Physics Chapter 7 Competency-Based Questions
Question 1: Study the following statements carefully.
- Electric and magnetic fields have zero average value in a plane em wave.
- For an em wave, the ratio k/ω is independent of wavelength.
- In an em wave, the E and B fields vary with the same frequency and are in
opposite phase.
- Since E = cB, the energy associated with the electric field is much greater
than that associated with the magnetic field.
Identify the correct option.
- only A and B are correct
- only C and D are correct
- only A and C are correct
- only B and D are correct
Question 2: Which of the following statement/s are incorrect?
- The displacement current flows in a dielectric of the capacitor when the
potential difference across its plates is decreasing with time.
- The direction of propagation of electromagnetic waves is given by
- The dimensions of are the same as that of electric voltage.
- Instantaneous energy flow rate is a constant for an electromagnetic wave.
- Light of uniform intensity shines perpendicularly on a totally absorbing surface.
On decreasing the area of the surface, the intensity remains the same.
- Only statements A & B
- Only statements C & D
- Only statements D & E
- Only statements A, C & D
Question 3: The diagrams below show the electric and magnetic field components of an electromagnetic wave at a certain time and location. Which of these electromagnetic waves are travelling towards you?
- only the em wave in Fig I
- only the em wave in Fig I and II
- only the em wave in Fig II and III
- only the em wave in Fig II, III and IV
Question 4: An electromagnetic wave of frequency 1 GHz travels through an empty space along the z‐direction. At a specific point in space, the electric field E attains a maximum value of 50 V/m. If the electric wave is polarized along x‐axis, then, (a) explain and identify the plane in which the magnetic field B will lie. (b) express the electric and magnetic fields as a function ofz and t.
Question 5: In a spaceship orbiting around the Earth, two astronauts stationed 2 m apart are speaking to each other. The conversation is transmitted to Earth via electromagnetic waves. Given that the sound waves travel through the air between the two astronauts in exactly the same time as the em waves take to reach the Earth ground station. Calculate the distance of the spaceship from the ground station. Take speed of sound in the air between the two astronauts as 340 m/s.
Question 6: An unfortunate nuclear explosion leaves behind the residual gamma radiations in the vicinity of the explosion site with an average energy density of 4 × 10−14 J/m3. (a) What is the rms value of the electric field of the radiation? (b) Compare the electric field strength with the magnetic field strength in this residual radiation.
Question 7: A dish antenna with a circular aperture of a radius 20 cm, receives digital TV signals from a satellite. The average intensity of the em waves that carry a particular TV program is 5 x 10‐14 W/m2. Determine the following: (a) electromagnetic energy delivered to the dish during the telecast of 30 minutes of a programme. (b) average energy density of the em wave.
Question 8: A laser emits a sinusoidal em wave of wavelength 10 μm along the x‐axis. The E field of the wave is parallel to the –ve z‐axis with a maximum value of 1 MV/m. Express the wave equation for E and B for this wave with all appropriate values and directions.
Question 9: A satellite at a height of 100 km from the Earth’s surface detects a radio signal emitted by a radio station on the ground. If the average power of the signal received is 100 kW, find the amplitudes E0 and B0 of the incoming signal.
To access all the practice question of Physics Chapter 7 Electromagnetic Waves, the complete FREE PDFs are attached here. Click on the 'Download PDF' to get the PDF.
CBSE Class 12 Physics Competency-Based Questions With Answer Key 2024-25 | Download 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.
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