CBSE Class 12 Physics Important Questions 2023-24

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CBSE Class 12 Physics Important Questions 2023-24: The CBSE class 12 Physics Syllabus 2023-24 comprises 10 units with 15 important chapters that cover a variety of topics and sub-topics. Each chapter holds respective importance and is chosen to develop a conceptual understanding of the students. The Central Board of Secondary Education is likely to conduct the CBSE 12th Board Exam 2024 between February 15 and April 10, 2024 in pen and paper mode. The detailed CBSE class 12 timetable 2024 will be released on December 29, 2023 tentatively. Students are advised to complete the CBSE class 12 syllabus 2023-24 beforehand and check the important or repeated questions that they can get in the CBSE 12th Exam 2024. Here, chapter wise CBSE Class 12 Physics important questions along with the weightage wise important questions are given for the students to improve their CBSE 12th preparation 2024.

Additionally, the board exam appearing students must also practice the CBSE class 12 previous year questions and CBSE class 12 sample papers within the allotted time on a regular basis. Not only this will boost their confidence level but also allow them to have an idea of the important and repeated questions of the CBSE 12th Physics Exam 2024. 

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CBSE Class 12 Physics Important Questions 2023-24: High Weightage Questions

The maximum weightage of the questions in the CBSE Class 12 Physics Exam will be 5 marks. Section D will contain 3 questions of 5 marks each. Below we have provided the highest weightage carrying CBSE Class 12 Physics important questions.

Question 1: (a) Describe briefly the process of transferring the charge between the two plates of a parallel plate capacitor when connected to a battery. Derive an expression for the energy stored in a capacitor. 

(b) A parallel plate capacitor is charged by a battery to a potential difference V. It is disconnected from battery and then connected to another uncharged capacitor of the same capacitance. Calculate the ratio of the energy stored in the combination to the initial energy on the single capacitor.

Question 2: The following figure shows a circuit diagram. We can find the currents through and potential differences across different resistors using Kirchhoff’s Rule.

Answer the following questions based on the above: (a) Which points are at the same potential in the circuit? (b) What is the current through arm bg? (c) Find the potential difference across resistance R3. 

Question 3: (a) Three charges –q, Q and –q are placed at equal distances on a straight line. If the potential energy of the system of these charges is zero, then what is the ratio Q:q? 

(b)(i) Obtain the expression for the electric field intensity due to a uniformly charged spherical shell of radius R at a point distant r from the centre of the shell outside it. (ii) Draw a graph showing the variation of electric field intensity E with r, for r > R and r < R.  

Question 4: Derive the expression for the torque acting on the rectangular current carrying coil of a galvanometer. Why is the magnetic field made radial? 

(b) An -particle is accelerated through a potential difference of 10 kV and moves along x-axis. It enters in a region of uniform magnetic field B = 2  10–3 T acting along y-axis. Find the radius of its path. (Take mass of -particle = 6·4  10–27 kg )

Question 5: Draw the ray diagram of an astronomical telescope when the final image is formed at infinity. Write the expression for the resolving power of the telescope. 

(b) An astronomical telescope has an objective lens of focal length 20 m and eyepiece of focal length 1 cm. (i) Find the angular magnification of the telescope. (ii) If this telescope is used to view the Moon, find the diameter of the image formed by the objective lens. Given the diameter of the Moon is 3·5  106 m and radius of lunar orbit is 3·8  108 m.

Also Check: CBSE Class 12 Exam Pattern 2023-24

CBSE Class 12 Physics Important Questions 2023-24: 3 Mark Questions

Section C of the CBSE Class 12 Physics question paper will contain 12 questions of 3 marks each, which is the next high weightage carrying question. Here 3 marks questions are provided:

Question 1: (a) If A and B represent the maximum and minimum amplitudes of an amplitude modulated wave, write the expression for the modulation index in terms of A & B. 

(b) A message signal of frequency 20 kHz and peak voltage 10 V is used to modulate a carrier of frequency 2 MHz and peak voltage of 15 V. Calculate the modulation index. Why the modulation index is generally kept less than one?

Question 2: Draw the energy level diagram for hydrogen atom. Mark the transitions corresponding to the series lying in the ultraviolet region, visible region and infrared region. 

Question 3: Two long straight parallel current carrying conductors are kept ‘a’ distant apart in air. The direction of current in both the conductors is same. Find the magnitude of force per unit length and direction of the force between them. Hence define one ampere.

Question 4: An a.c. source generating a voltage ε = ε0 sin ωt is connected to a capacitor of capacitance C. Find the expression for the current I flowing through it. Plot a graph of ε and I versus t to show that the current is ahead of the voltage by π/2. 

Question 5: The binding energies per nucleon of the parent nucleus, the daughter nucleus and -particle are 7·8 MeV, 7·835 MeV and 7·07 MeV, respectively. Assuming the daughter nucleus to be formed in the unexcited state and neglecting its share in the energy of the reaction, find the speed of the emitted -particle. (Mass of -particle = 6·68  10–27 kg)
Quick Links:

• CBSE Class 12 Physics Syllabus 2023-24
• CBSE Class 12 Physics Previous Year Question Papers
• CBSE Class 12 Physics Sample Paper 2023-24

CBSE Class 12 Physics Important Questions 2023-24: 1 Mark Questions

Go through the 1 mark CBSE Class 12 Physics Important Questions given below:

Question 1: How does the mobility of electrons in a conductor change, if the potential difference applied across the conductor is doubled, keeping the length and temperature of the conductor constant? 

Question 2: Why cannot we use Si and Ge in fabrication of visible LEDs?

Question 3: How does an increase in doping concentration affect the width of depletion layer of a p-n junction diode?

Question 4: Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below. 

1. a) Both A and R are true and R is the correct explanation of A 
2. b) Both A and R are true and R is NOT the correct explanation of A 
3. c) A is true but R is false 
4. d) A is false and R is also false 

Assertion(A): The photoelectrons produced by a monochromatic light beam incident on a metal surface have a spread in their kinetic energies. Reason(R): The energy of electrons emitted from inside the metal surface, is lost in collision with the other atoms in the metal.  

Question 5: . When alpha particles are sent through a thin gold foil, most of them go straight through the foil, because 

(a) alpha particles are positively charged 

(b) the mass of an alpha particle is more than the mass of an electron 

(c) most of the part of an atom is empty space 

(d) alpha particles move with high velocity 

CBSE Class 12 Physics Important Questions: Chapter-wise Questions

In this section, the high weightage carrying chapter wise questions of CBSE Class 12 Physics are provided. 

Chapter 8: Electromagnetic Waves

Question 1: A capacitor has been charged by a dc source. What are the magnitudes of conduction and displacement currents, when it is fully charged? (2 marks)

Question 2: When an ideal capacitor is charged by a dc battery, no current flows. However, when an ac source is used, the current flows continuously. How does one explain this, based on the concept of displacement current? (2 marks)

Question 3: (a) How are electromagnetic waves produced?

(b) How do you convince yourself that electromagnetic waves carry energy and momentum? (2 marks)

Chapter 9: Ray Optics and Optical Instruments

Question 1: State the conditions for the phenomenon of total internal reflection to occur. (2 marks)

Question 2: A converging lens is kept coaxially in contact with a diverging lens — both the lenses being of equal focal lengths. What is the focal length of the combination? (2 marks)

Question 3: How would a biconvex lens appear when placed in a trough of liquid having the same refractive index as that of the lens? (2 marks)

Chapter 10: Wave Optics

Question 1: Laser light of wavelength 640 nm incident on a pair of slits produces an interference pattern in which the bright fringes are separated by 7.2 mm. Calculate the wavelength of another source of light which produces interference fringes separated by 8.1 mm using same arrangement. Also find the minimum value of the order ‘n’ of bright fringe of shorter wavelength which coincides with that of the longer wavelength. (3 marks)

Question 2: Yellow light (λ = 6000Å) illuminates a single slit of width 1 x 10-4 m. Calculate

(i) the distance between the two dark lines on either side of the central maximum, when the diffraction pattern is viewed on a screen kept 1.5 m away from the slit;

(ii) the angular spread of the first diffraction minimum. (2 marks)

Question 3: A parallel beam of light of 600 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1.2 m away. It is observed that the first minimum is at a distance of 3 mm from the centre of the screen. Calculate the width of the slit. (2 marks)

All the students should prepare the answers to the CBSE Class 12 Physics important questions mentioned above properly. To get more details on Board Exams and Education News stay tuned to CollegeDekho!