The Central Board of Secondary Education (CBSE) class 12 board exams are a crucial milestone for every student in India. It is an examination that is often regarded as the stepping stone towards a bright future, as the marks obtained in these exams can determine the course of a student’s academic and professional life. To score well in the CBSE class 12 board exams, it is essential to practice questions regularly. Here are some reasons why practicing questions is so important:
1. Helps in Time Management:
Practicing questions helps students learn time management skills. CBSE class 12 exams have a set time limit, and students must complete the paper within that time frame. By practicing questions regularly, students can learn to manage their time effectively and become more efficient at answering questions in the given time frame.
2. Enhances Problem Solving Skills:
Practicing questions regularly enhances students’ problem-solving skills. It helps students develop a clear understanding of the concepts and principles involved, enabling them to apply their knowledge to solve complex problems. This not only helps in the CBSE class 12 board exams but also prepares students for various competitive exams that they may have to take later in their academic or professional life.
3. Boosts Confidence:
Practicing questions regularly boosts students’ confidence levels. Solving a wide range of questions helps them identify their strengths and weaknesses, giving them the confidence to tackle any type of question that comes their way during the exams. It also helps them build a positive attitude towards the exams and their own abilities, which is essential for success.
4. Provides Insight into Exam Patterns:
Practicing questions provides students with insights into the exam patterns and the types of questions that may appear in the CBSE class 12 board exams. This helps them to prepare more effectively, focusing on the areas where they need to improve and making sure that they are familiar with the type of questions that they may encounter during the exam.
5. Improves Speed and Accuracy:
Practicing questions regularly also helps improve students’ speed and accuracy. With regular practice, students can learn to solve problems more quickly and accurately, reducing the chances of making mistakes during exams. This not only helps them score more marks but also helps them complete the paper within the allotted time.
Chapter-1: Electric Charge and Field
Q.1. Which orientation of an electric dipole in a uniform electric field would correspond stable equilibrium?
Q.2. Define electric dipole moment. Write its S.I. unit.
Q.3. A spherical conducting shell of inner radius r1 and outer radius r2 has a charge ‘Q’. A Charge ‘q’ is placed at the center of the shell.
(a) What is the surface charge density on the (i) inner surface, and (ii) outer surface of the shell?
(b) Write the expression for the electric field rice at a point x > r2 from the center of the shell.
Chapter-2: Electrostatic Potential and Capacitance
Q.1. What is the electrostatic potential due to an electric dipole at an equatorial point?
Q.2. Name the physical quantity whose S.I. unit JC−1. is it a scalar or a vector quantity?
Q.3. A test charge ‘q’ is moved without acceleration from A to C along the path from A to B and then from B to C in electric field E as shown in the figure. (i) Calculate the potential difference between A and C. (ii) At which point (of the two) is the potential more and why?
Chapter-3: Current Electricity
Q.1. State the reason, why GaAs is most commonly used in the making of a solar cell.
Q.2. Two conducting wires X and Y of the same diameter but different materials are joined in series across a battery. If the number density of electrons X is twice that in Y, find the ratio of the drift velocity of electrons in the two wires.
Q.3. (i) State the principle of working of a meter bridge.
(ii) In a meter bridge balance point is found at a distance 1 with resistance R and S as shown in the figure. When an unknown resistance X is connected in parallel with the resistance S, the balance point shifts to a distance a l2 find the expression for X terms of l1, l2, and S.
Chapter-4: Moving Charges and Magnetism
Q.1. Why should the spring? suspension in a moving coil galvanometer has a low
torsional constant?
Q.2. An electron does not suffer any deflection while passing through a region of
the uniform magnetic field. What is the direction of the magnetic field?
Q.3. (a) Using Ampere’s circuital law, obtain the expression for the magnetic field due to a long solenoid at a point inside the solenoid on its axis.
(b) In what respect is a toroid different from a solenoid? Draw and compare the pattern of the magnetic field lines in the two cases.
(c) How is the magnetic field inside a given solenoid made strong?
Chapter-5: Magnetism and Matter:
Q1. How does the intensity of magnetization of a paramagnetic material vary with an increasing applied magnetic field?
Q2. How will the magnetic field intensity at the centre of a circular wire carrying current change, if the current through the wire is doubled and the radius of the coil is halved?
Q3. Write an expression for the force experienced by the charged particle moving in a uniform magnetic field B with the help of a labeled diagram explaining the working of cyclotrons. Show that cyclotron frequency does not depend upon the speed of the particle.
Chapter-6: Moving Charges and Magnetism
Q.1. Define self-inductance of a coil. Write its S.I. units.
Q.2. A bar magnet is moved in the direction indicated by the arrow between two coils PQ and CD. Predict the direction of induced current in each coil.
Q.3. (a) State Lenz’s law. Give one example to illustrate this law. The Lenz’s is a
consequence of the principle of conservation of energy. ‘Justify this statement.
(b) Deduce an expression for the inductance of two long coaxial solenoids but having different radii and a different number of turns.
Chapter-7: Alternating Current
Q.1. The instantaneous current and voltage of a.c. circuit are given by i = 10 sin 300 tA and v = 200 sin 300 tV. What is power dissipation in the circuit?
Q.2. Why is the use of A.C. voltage preferred over D.C. voltage? Give two reasons.
Q.3. Draw a schematic diagram of a step-up transformer. Explain its working principle. Deduce the expression for the secondary to primary voltage in terms of the number of turns in the two coils. In an ideal transformer, how is this ratio related to the currents in the two coils? How is the transformer used in large-scale transmission and distribution of electrical energy over long distances?
Chapter-8: Electromagnetic Waves
Q.1. Name the EM waves used for studying the crystal structure of solids. What is its frequency range?
Q.2. What are the direction of electric and magnetic field vectors relative to each other and relative to the direction of propagation of electromagnetic waves?
Q.3. Answer the following:
(a) Name the em waves which are suitable for radar systems used in aircraft navigation. Write the range of frequency of these waves.
(b) If the earth did not have an atmosphere, would its average surface temperature be higher or lower than what it is now? Explain.
(c) An em wave exerts pressure on the surface on which it is incident. Justify.
Chapter-9: Ray Optics and Optical instruments
Q.1. How does the angle of minimum deviation of a glass prism vary, if the incident light is replaced with a red light?
Q.2. Why does the bluish color predominate in a clear sky?
Q.3. What is plane-polarized light? Two polaroids are placed at 900 to each other and the transmitted intensity is zero. What happens when one more polaroid is placed between these two bisecting the angle between them? how will the intensity of transmitted light vary on further rotting the polaroid?
Chapter-10: Wave Optics:
Q.1. How would the angular separation of interference fringes in young’s double slit experiment change when the distance between the slits and screen is doubled?
Q.2. How does the angular separation between fringes in a single-slit diffraction
experiment change when the distance of separation between the slit and screen is
Doubled?
Q.3. State the importance of coherent sources in the phenomenon of interference. In Young’s double slit experiment to produce an interference pattern, obtain the conditions for constructive and destructive interference. Hence deduce the expression for the fringe width. How does the fringe width get affected, if the entire experimental apparatus of Young is immersed in water?
Chapter-11: Dual nature of radiation and matter
Q.1. The stopping potential in an experiment on photoelectric effect is 1. 5 V. what is the maximum kinetic energy of the photoelectron emitted?
Q.2. When light travels from a rarer to a denser medium, the speed decreases. Does
this decrease in speed imply a decrease in the energy carried by the light wave? Justify your answer.
Chapter-12: Atom
Q.1. Define ionization energy. What is its value for a hydrogen atom?
Q.2. Write the expression for the de Broglie wavelength associated with a charged
particle having charge ‘q’ and mass ‘m’, when it is accelerated by a potential V.
Chapter-13: Nuclei
Q.1. State two characteristic properties of nuclear force:
Q.2. Two nuclei have mass numbers in the ratio 1: 8 what is the ratio of their
nuclear radii?
Chapter-14: Semiconductor Electronics, Materials, Devices and Simple circuits
Q.1. Give the logic symbol of the NOR gate.
Q.2. What happens to the width of the depletion layer of a p-n junction when it is (i) forward-biased, and (ii) reverse-biased?
Q.3.(a) Draw the circuit arrangement for studying the input and output characteristics of an n-p-n transistor in CE configuration, with the help of these characteristics define (i) input resistance. (ii) current amplification factor.
(b) Describe briefly with the help of a circuit diagram how the n-p-n transistor is used to produce self-sustained oscillations.
Chapter-15: Communication Systems
Q.1. What is sky wave propagation?
Q.2. The carrier wave is given by C (t) = 2sin (8Ï€ t) volt.
The modulating signal is a square wave as shown. Find modulation index.
Q.3. What does the term LOS communication mean? Name the types of waves that are used for this communication. Which of the two heights of the height of transmitting antenna and the height of receiving antenna can affect the range over which this mode of communication remains effective?
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CBSE Class 11th Physics Exam Preparation Tips
Cbse Class 11 Physics Practical Syllabus
A scalar quantity is a quantity that has only magnitude, such as temperature, mass, or speed. A vector quantity, on the other hand, has both magnitude and direction, such as velocity, force, or acceleration. The law of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed from one form to another. In other words, the total energy of a closed system remains constant. Potential energy is the energy that an object possesses due to its position or state, while kinetic energy is the energy that an object possesses due to its motion. Potential energy can be converted into kinetic energy, and vice versa. The principle of superposition states that when two or more waves or other disturbances are present at the same time, the total disturbance at any point is equal to the sum of the disturbances produced by each individual wave. A conductor is a material or object that allows electric current to flow through it easily, while an insulator is a material or object that does not allow electric current to flow through it easily. This is due to the difference in the ability of the materials to conduct electricity. Conductors have free electrons that can move easily through the material, while insulators have tightly bound electrons that do not move easily. CBSE Physics Important Questions FAQs
What is the difference between a scalar quantity and a vector quantity in physics?
What is the law of conservation of energy in physics?
What is the difference between potential energy and kinetic energy in physics?
What is the principle of superposition in physics?
What is the difference between a conductor and an insulator in physics?
