CBSE Class 12 Physics 2023
301 questions · 568 marks · 296 with the board’s own marking-scheme answer, 5 with no official answer on the site.
Marks by chapter
Counted from the 301 questions listed below, as the 2023 papers print them. CBSE allocates marks per unit, not per chapter — this is what was observed, not an official CBSE weightage. Every year compared →
| Chapter | Marks | Share |
|---|---|---|
| Current Electricity39 questions | 68 | 12.0% |
| Ray Optics and Optical Instruments26 questions | 68 | 12.0% |
| Moving Charges and Magnetism29 questions | 57 | 10.0% |
| Dual Nature of Radiation and Matter29 questions | 47 | 8.3% |
| Semiconductor Electronics: Materials, Devices and Simple Circuits29 questions | 46 | 8.1% |
| Electromagnetic Induction20 questions | 45 | 7.9% |
| Alternating Current19 questions | 43 | 7.6% |
| Electric Charges and Fields20 questions | 42 | 7.4% |
| Nuclei19 questions | 33 | 5.8% |
| Atoms18 questions | 32 | 5.6% |
| Wave Optics16 questions | 29 | 5.1% |
| Electromagnetic Waves17 questions | 25 | 4.4% |
| Electrostatic Potential and Capacitance10 questions | 21 | 3.7% |
| Magnetism and Matter10 questions | 12 | 2.1% |
301 questions from 2023
- Q1A charge Q is placed at the centre of a cube. The electric flux through one if its face is1 mk
- Q1The ratio of the magnitudes of the electric field and magnetic field of a plane electromagnetic wave is1 mk
- Q1An electric dipole of length 2 cm is placed at an angle of 30^° with an electric field 2 × 10^5 N / C. If the dipole…1 mk
- Q1A battery of emf E and internal resistance r is connected to an external circuit. The potential drop within the battery…1 mk
- Q1An electron experiences a force (1 · 6 × 10^-16 N) i in an electric field E. The electric field E is:1 mk
- Q1The magnitude of the electric field due to a point charge object at a distance of 4.0 m is 9 N / C. From the same…1 mk
- Q1Two charges q_1 and q_2 are placed at the centres of two spherical conducting shells of radius r_1 and r_2…1 mk
- Q1Two identical circular coaxial coils A and B, arranged in vertical planes parallel to each other, carry currents in the…1 mk
- Q2A steady current flows through a metallic wire whose area of cross-section increases continuously from one end of the…1 mk
- Q2The energy of a photon of wavelength 663 nm is1 mk
- Q2A point P lies at a distance x from the mid point of an electric dipole on its axis. The electric potential at point P…1 mk
- Q2An electron enters a uniform magnetic field with speed v. It describes a semicircular path and comes out of the field.…1 mk
- Q2Two long parallel wires kept 2 m apart carry 3A current each, in the same direction. The force per unit length on one…1 mk
- Q2The momentum of a photon of wavelength λ is:1 mk
- Q2Which one of the following is not a scalar quantity?1 mk
- Q2Two horizontal thin long parallel wires, separated by a distance r carry current I each in the opposite directions. The…1 mk
- Q2Specify the transition of electron in the wavelength of the line in the Bohr model of hydrogen atom which gives rise to…1 mk
- Q2A light of frequency v is incident on a metal surface whose work function is W_0. The kinetic energy of emitted…1 mk
- Q2For a metallic conductor, the correct representation of variation of resistance R with temperature T is:1 mk
- Q3Two thin long parallel wires A and B are separated by a distance r and carry current I each in the same direction. The…1 mk
- Q3The current density due to drift of electrons in a conductor is given by: (symbols have their usual meanings)1 mk
- Q3The minimum distance between an object and its real image formed by a convex lens of focal length f is:1 mk
- Q3Which of the following has its permeability less than that of free space?1 mk
- Q3A current of 0.8 A flows in a conductor of 40 Ω for 1 minute. The heat produced in the conductor will be1 mk
- Q3The potential difference across a cell in an open circuit is 8 V. It falls to 4 V when a current of 4 A is drawn from…1 mk
- Q3An electromagnetic wave is produced by a charge1 mk
- Q3At a certain temperature in an intrinsic semiconductor, the electrons and holes concentration is 1.5 × 10^16 m^-3. When…1 mk
- Q3The magnetic field lines near a substance are as shown in the figure. The substance is:1 mk
- Q3Which of the following cannot modify an external magnetic field as shown in the figure?1 mk
- Q4Photons of energy 4 · 3 eV are incident on a photosensitive surface of work function 2 · 3 eV. The stopping potential…1 mk
- Q4A photon of energy 7 eV is incident on a metal surface having the work function of 3.75 eV. The stopping potential is:1 mk
- Q4A particle of mass m and charge -q is moving with a uniform speed v in a circle of radius r, with another charge q at…1 mk
- Q4A cell of emf E is connected across an external resistance R. When current ' I ' is drawn from the cell, the potential…1 mk
- Q4A square shaped coil of side 10 cm, having 100 turns is placed perpendicular to a magnetic field which is increasing at…1 mk
- Q4The figure shows variation of current (I) with time ( t ) in four devices P, Q, R and S. The device in which an…1 mk
- Q4An infinitely long uniformly charged wire produces an electric field of 18 × 10^4 NC^-1 at a distance of 1 · 0 cm. The…1 mk
- Q4A semiconductor device is connected in series with a battery, an ammeter and a resisitor. A current flows in the…1 mk
- Q4Two wires of equal length and radii r and 2 r are connected in series. Their resistivities are 2 ρ and ρ respectively.…1 mk
- Q5Beams of electrons and protons move parallel to each other in the same direction. They1 mk
- Q5The electromagnetic waves used in radar systems are:1 mk
- Q5A particle of mass m and charge q moving with a uniform velocity v=v_0 x i+v_0 y j enters a region with a magnetic…1 mk
- Q5Which one of the following electromagnetic radiation has the least wavelength?1 mk
- Q5At 0 K, the resistivity of an intrinsic semiconductor is:1 mk
- Q5A capacitor is charged by a battery. Between the plates, during process of charging:1 mk
- Q5Choose the correct option related to wavelengths ( λ ) of different parts of electromagnetic spectrum.1 mk
- Q5An isolated point charge particle produces an electric field E at a point 3 m away from it. The distance of the point…1 mk
- Q5A diamagnetic substance is brought near the north or south pole of a bar magnet. It will be:1 mk
- Q6An inductor, a capacitor and a resistor are connected in series across an ac source of voltage. If the frequency of the…1 mk
- Q6In a Young's double-slit experiment, the fringe width is found to be β. If the entire apparatus is immersed in a liquid…1 mk
- Q6The atomic number of an atom represents:1 mk
- Q6A long straight wire of radius 'a' carries a steady current ' I '. The current is uniformly distributed across its area…1 mk
- Q6In a Young's double-slit experiment, the screen is moved away from the plane of the slits. What will be its effect on…1 mk
- Q6A point charge q is kept at a distance r from an infinitely long straight wire with charge density λ. The magnitude of…1 mk
- Q6The radius of _13^27 X nucleus is R. The radius of _53^125 Y nucleus will be1 mk
- Q6Which one of the following has relative magnetic permeability between 0 and 1?1 mk
- Q6A circular coil of radius 8.0 cm and 40 turns is rotated about its vertical diameter with an angular speed of 25/(π)…1 mk
- Q6In an experiment, photons of energy 7 · 5 eV are incident on a metal surface. Electrons emitted from the metal surface…1 mk
- Q7E and B represent the electric and the magnetic field of an electro- magnetic wave respectively. The direction of…1 mk
- Q7Photons of energy 3 · 2 eV are incident on a photosensitive surface. If the stopping potential for the emitted…1 mk
- Q7Figure shows a rectangular conductor PSRQ in which movable arm PQ has a resistance ' r ' and resistance of PSRQ is…1 mk
- Q7E, c and v represent the energy, velocity and frequency of a photon. Which of the following represents its wavelength?1 mk
- Q7The electromagnetic radiations used to kill germs in water purifiers are called:1 mk
- Q7In an experiment on photoelectric effect, the intensity of incident radiation is increased, keeping the frequency v the…1 mk
- Q7The ratio of the magnitude of magnetic moment to that of angular momentum, of an electron revolving around the nucleus…1 mk
- Q7The energy of a photon of wavelength λ is1 mk
- Q7An electric dipole of dipole moment 2 × 10^-8 C-m in a uniform electric field experiences a maximum torque of 6 × 10^-4…1 mk
- Q7A steady current of 8 mA flows through a wire. The number of electrons passing through a cross-section of the wire in…1 mk
- Q7For the forward biasing of a p-n junction diode, which of the following statements is not correct?1 mk
- Q8Two nuclei have their mass numbers in the ratio of 8: 1. The ratio of their nuclear densities is:1 mk
- Q8In the process of charging of a capacitor, the current produced between the plates of the capacitor is:1 mk
- Q8Which of the following statements is not true for nuclear forces?1 mk
- Q8Which one of the following has negative value of susceptibility?1 mk
- Q8Name the electromagnetic waves also known as 'heat waves'.1 mk
- Q8The SI unit of mobility of charge carriers is:1 mk
- Q8In the wave picture of light, the intensity I of light is related to the amplitude A of the wave as:1 mk
- Q8The ratio of the nuclear densities of two nuclei having mass numbers 64 and 125 is1 mk
- Q8A ray of monochromatic light propagating in air, is incident on the surface of water. Which of the following will be…1 mk
- Q8Which one of the following elements will require the highest energy to take out an electron from them? Pb, Ge, C and Si1 mk
- Q9A point charge q_0 is moving along a circular path of radius a, with a point charge -Q at the centre of the circle. The…1 mk
- Q9During the formation of a p-n junction.1 mk
- Q9A conductor of 10 Ω is connected across a 6 V ideal source. The power supplied by the source to the conductor is1 mk
- Q9A beam of light travels from air into a medium. Its speed and wavelength in the medium are 1.5 × 10^8 ms^-1 and 230 nm…1 mk
- Q9The difference in mass of ^7 X nucleus and total mass of its constituent nucleons is 21.00 u. The binding energy per…1 mk
- Q9The energy required by an electron to jump the forbidden band in silicon at room temperature is about1 mk
- Q9For a concave mirror of focal length ' f ', the minimum distance between the object and its real image is:1 mk
- Q9In a single-slit diffraction experiment, the width of the slit is halved. The width of the central maximum, in the…1 mk
- Q9During the formation of a p-n junction:1 mk
- Q10The number of electrons flowing through a conductor per second is 3 · 3 × 10^19. The current flowing through the…1 mk
- Q10The threshold voltage for a p-n junction diode used in the circuit is 0 · 7 V. The type of biasing and current in the…1 mk
- Q10Which one of the following metals does not exhibit emission of electrons from its surface when irradiated by visible…1 mk
- Q10The diagram shows four energy level of an electron in Bohr model of hydrogen atom. Identify the transition in which the…1 mk
- Q10In a moving coil galvanometer, the deflecting torque τ acting on the coil is related to the current I flowing through…1 mk
- Q10The diagram shows four energy level of an electron in Bohr model of hydrogen atom. Identify the transition in which the…1 mk
- Q10A graph is plotted between the stopping potential (on y -axis) and the frequency of incident radiation (on x -axis) for…1 mk
- Q11The direction of induced current in the loop abc is:1 mk
- Q11Hydrogen atom initially in the ground state, absorbs a photon which excites it to n=5 level. The wavelength of the…1 mk
- Q11Which of the following graphs correctly represents the variation of a particle momentum with its associated de-Broglie…1 mk
- Q11Which of the following graphs correctly represents the variation of a particle momentum with its associated de-Broglie…1 mk
- Q11The current in a device varies with time t as I=6 t, where I is in mA and t is in s. The amount of charge that passes…1 mk
- Q11Figure shows a plot of stopping potential (V_0) versus 1/(λ), where λ is the wavelength of the radiation causing…1 mk
- Q11A hydrogen atom makes a transition from n=5 to n=1 orbit. The wavelength of photon emitted is λ. The wavelength of…1 mk
- Q11Light of frequency 6.4 × 10^14 Hz is incident on a metal of work function 2 · 14 eV. The maximum kinetic energy of the…1 mk
- Q11A plane wavefront is incident on a concave mirror of radius of curvature R. The radius of the refracted wavefront will…1 mk
- Q12A ray of light travels a distance of 12.0 m in a transparent sheet in 60 ns. The refractive index of the sheet is1 mk
- Q12A photon of wavelength 663 nm is incident on a metal surface. The work function of the metal is 1.50 eV. The maximum…1 mk
- Q12The ratio of maximum frequency and minimum frequency of light emitted in Balmer series of hydrogen spectrum, in Bohr's…1 mk
- Q12An ac voltage v=v_0 sin ω t is applied to a series combination of a resistor R and an element X. The instantaneous…1 mk
- Q12The mass density of a nucleus of mass number A is:1 mk
- Q12The capacitors, each of 4 μ F are to be connected in such a way that the effective capacitance of the combination is 6…1 mk
- Q12Electromagnetic waves of wavelength of the order of a few meters were first produced and detected in the laboratory by:1 mk
- Q12A proton and an alpha particle have the same kinetic energy. The ratio of de Broglie wavelengths associated with the…1 mk
- Q12The curve of binding energy per nucleon as a function of atomic mass number has a sharp peak for helium nucleus. This…1 mk
- Q13The emf and internal resistance of a cell are E and r respectively. It is connected across an external resistance R=2…1 mk
- Q13Which of the following statements about a series LCR circuit connected to an ac source is correct?1 mk
- Q13An ideal inductor is connected across an AC source of voltage. The current in the circuit1 mk
- Q13In an extrinsic semiconductor, the number density of holes is 4 × 10^20 m^-3. If the number density of intrinsic…1 mk
- Q13The masses of two cylindrical wires of copper are in the ratio of 1: 3 and their lengths are in the ratio of 5: 3. The…1 mk
- Q13Which of the following pairs of media has the least value of critical angle?1 mk
- Q13An ac source of voltage is connected in series with a p-n junction diode and a load resistor. The correct option for…1 mk
- Q13What is the ratio of inductive and capacitive reactance in an ac circuit?1 mk
- Q13The potential energy of an electron in the second excited state in hydrogen atom is:1 mk
- Q14Pieces of copper and of silicon are initially at room temperature. Both are heated to temperature T. The conductivity of1 mk
- Q14According to Huygens principle, the amplitude of secondary wavelets is1 mk
- Q14Which one of the following is the correct representation of variation of conductivity of a conductor with temperature?1 mk
- Q14If a p-n junction diode is reverse biased,1 mk
- Q14When an intrinsic semiconductor is doped with a small amount of trivalent impurity, then:1 mk
- Q14Two cells of emf E each and internal resistances r and 2 r are connected in parallel as shown in the figure. The…1 mk
- Q14A ray of light of wavelength 600 nm propagates from air into a medium. If its wavelength in the medium becomes 400 nm,…1 mk
- Q14In an interference experiment, third bright fringe is obtained at a point on the screen with a light of 700 nm. What…1 mk
- Q14A bar magnet is dropped in a hollow metallic cylinder along its vertical axis. The acceleration of the falling magnet…1 mk
- Q15The radius of the n^th orbit in Bohr model of hydrogen atom is proportional to1 mk
- Q15The correct graph showing the variation of the resistance (R) of a cylindrical metal wire as a function of its radius (…1 mk
- Q15Which of the following graphs correctly represents the variation of the magnitude of the magnetic field outside a…1 mk
- Q15A point charge situated at a distance ' r ' from a short electric dipole on its axis, experiences a force F. If the…1 mk
- Q15A voltage signal is described by: v =V_0, for 0 ≤ t ≤ T/2; =0, for T/2 ≤ t ≤ T for a cycle. Its rms value is:1 mk
- Q15In the energy-band diagram of n-type Si, the gap between the bottom of the conduction band E_C and the donor energy…1 mk
- Q15The formation of depletion region in a p-n junction diode is due to1 mk
- Q16Assertion: The resistance of an intrinsic semiconductor decreases with increase in its temperature. Reason (R): The…1 mk
- Q16Assertion: When a bar of copper is placed in an external magnetic field, the field lines get concentrated inside the…1 mk
- Q16Assertion: When three electric bulbs of power 200 W, 100 W and 50 W are connected in series to a source, the power…1 mk
- Q16Assertion: The internal resistance of a cell is constant. Reason (R): Ionic concentration of the electrolyte remains…1 mk
- Q16Assertion: In insulators, the forbidden gap is very large. Reason (R): The valence electrons in an atom of an insulator…1 mk
- Q16Assertion: Diamagnetic substances exhibit magnetism. Reason (R): Diamagnetic materials do not have permanent magnetic…1 mk
- Q17Assertion: The phase difference between any two points on a wavefront is zero. Reason (R): All points on a wavefront…1 mk
- Q17Assertion: The given figure does not show a balanced Wheatstone bridge. Reason (R): For a balanced bridge small current…1 mk
- Q17Assertion: When radius of a circular loop carrying a steady current is doubled, its magnetic moment becomes four times.…1 mk
- Q17Assertion: A current carrying square loop made of a wire of length L is placed in a magnetic field. It experiences a…1 mk
- Q17Assertion: The equivalent resistance between points A and B in the given network is 2 R. Reason (R): All the resistors…1 mk
- Q17Assertion: Work done in moving a charge around a closed path, in an electric field is always zero. Reason (R):…1 mk
- Q18Assertion: In Young's double slit experiment all fringes are of equal width. Reason (R): The fringe width depends upon…1 mk
- Q18Assertion: The nucleus _3^7 X is more stable than the nucleus _3^4 Y. Reason (R):_3^7 X contains more number of protons.1 mk
- Q18Assertion: In 'n' type semiconductor, number density of electrons is greater than the number density of holes but the…1 mk
- Q18Assertion: Photoelectric effect demonstrates the particle nature of light. Reason ( R ): Photoelectric current is…1 mk
- Q18Assertion: The deflecting torque acting on a current carrying loop is zero when its plane is perpendicular to the…1 mk
- Q19Draw a graph showing the variation of potential energy of a pair of nucleons as a function of their separation.…2 mk
- Q19Draw a graph showing the variation of potential energy of a pair of nucleons as a function of their separation.…2 mk
- Q19Briefly explain why and how a galvanometer is converted into an ammeter.2 mk
- Q19An alpha particle is projected with velocity v=(3 · 0 × 10^5 m / s) i into a region in which magnetic field B=[(0 · 4…2 mk
- Q19Two identical dipoles are arranged in x-y plane as shown in the figure. Find the magnitude and the direction of net…2 mk
- Q19How is the width of depletion layer of a p-n junction diode affected when it is (i) forward biased, and (ii) reverse…2 mk
- Q19Plot a graph showing the variation of photo electric current, as a function of anode potential for two light beams…2 mk
- Q19The radii of curvature of the faces of a double-convex lens are 20 cm and 30 cm. Its power is 25/6 D. What is the…2 mk
- Q19In a Young's double slit experiment, the separation between the two slits is d and distance of the screen from the…2 mk
- Q19A wire of length l is in the form of a circular loop A of one turn. This loop is reshaped into loop B of three turns.…2 mk
- Q20Consider an induced magnetic field due to changing electric field and an induced electric field due to changing…2 mk
- Q20Answer the following giving reasons: Do the magnetic field lines also represent the 'lines of force' on a moving…2 mk
- Q20How are infrared waves produced? Why are these waves referred to as heat waves? Give any two uses of infrared waves. OR…2 mk
- Q20Briefly describe the multi-step process involved in the generation of energy in the Sun.2 mk
- Q20What is meant by the term 'displacement current'? Briefly explain how this current is different from a conduction…2 mk
- Q20How will the De Broglie wavelength associated with an electron be affected when the (i) velocity of the electron…2 mk
- Q20Write two differences between the emf and terminal potential difference of a cell. What is the most important…2 mk
- Q21Use Gauss's law to obtain the expression for electric field due to a thin infinitely long straight uniformly charged…2 mk
- Q21How are electromagnetic waves produced? Write their two characteristics.2 mk
- Q21A small magnetised needle P is placed at the origin of x-y plane with its magnetic moment pointing along the y -axis.…2 mk
- Q21Using Huygens' principle, draw a ray diagram showing the propagation of a plane wave refracting at a plane surface…2 mk
- Q21State Huygens' principle. How did Huygens explain the absence of the backwave? OR Use Huygens' principle to show…2 mk
- Q21Identify the electromagnetic radiation and write its wavelength range, which is used to kill germs in water purifier.…2 mk
- Q21With the help of a circuit diagram, explain how a full wave rectifier gives output rectified voltage corresponding to…2 mk
- Q21Identify the electromagnetic wave whose wavelengths range is from about 10^-12 m to about 10^-8 m. 10^-3 m to about…2 mk
- Q21In the given figure the radius of curvature of curved face in the plano- convex and the plano-concave lens is 15 cm…2 mk
- Q22Depict the orientation of an electric dipole in stable and unstable equilibrium in an external uniform electric field.…2 mk
- Q22The ground state energy of hydrogen atom is -13 · 6 eV in Bohr model. An electron makes a transition from an energy…2 mk
- Q22The refractive indices of two media A and B are 2 and √2 respectively. What is the critical angle for their interface?2 mk
- Q22An electric dipole of dipole moment ( p) is kept in a uniform electric field E. Show graphically the variation of…2 mk
- Q22A wire of length L is bent round in the form of (i) a square, and then (ii) an equilateral triangle. If current I is…2 mk
- Q22Two coherent monochromatic light beams of intensities I and 4 I superpose each other. Find the ratio of maximum and…2 mk
- Q22What is a displacement current? How is it different from a conduction current? OR Write any two characteristics of an…2 mk
- Q22A plane electromagnetic wave propagates in vacuum along x -axis. Give the direction of electric field and magnetic…2 mk
- Q22What happens to the interference pattern when two coherent sources are infinitely close, and far apart from each other2 mk
- Q22A cell of emf E and internal resistance r is connected to a variable resistance R. Draw plots showing the variation of…2 mk
- Q22Three point charges Q, q and -q are kept at the vertices of an equilateral triangle of side L as shown in figure. What…2 mk
- Q23A particle of charge q and mass m starts moving with uniform velocity v_0 i. Specify the direction of magnetic field…2 mk
- Q23The figure shows v_m^2 versus 1/(λ) graph for photoelectrons emitted from a surface where v_m is the maximum speed of…2 mk
- Q23Write the expression for the Lorentz force on a particle of charge q moving with a velocity v in a magnetic field B.…2 mk
- Q23Two identical circular loops P and Q, each of radius R carrying current I are kept in perpendicular planes such that…2 mk
- Q23What is meant by ionisation energy? Write its value for hydrogen atom. OR Define the term, mass defect. How is it…2 mk
- Q23The power of a thin lens is +5 D. When it is immersed in a liquid, it behaves like a concave lens of focal length 100…2 mk
- Q23Show that the density of a nucleus is independent of its mass number. Why are lighter nuclei more stable than heavier…2 mk
- Q23The ground state energy of hydrogen atom is -13.6 eV. What is the potential energy and kinetic energy of an electron in…2 mk
- Q23Draw a graph showing the variation of binding energy per nucleon as a function of mass number A. The binding energy per…2 mk
- Q23Two wires of equal lengths are shaped in the form of a square loop and a circular loop. Both loops are suspended in a…2 mk
- Q23Write the expression for the Lorentz force on a particle of charge q moving with a velocity v in a magnetic field B.…2 mk
- Q24Two conductors, made of the same material have equal lengths but different cross-sectional areas A_1 and A_2( A_1>A_2).…2 mk
- Q24Draw the graph showing the variation of binding energy per nucleon with mass number A of nuclei (2<A<170). Use this…2 mk
- Q24The potential difference applied across a given conductor is doubled. How will this affect (i) the mobility of…2 mk
- Q24A potential difference ( V ) is applied across a conductor of length ' L ' and cross-sectional area 'A'. How will the…2 mk
- Q24A double-convex lens of power 4 D is manufactured from a glass of refractive index 1 · 5. What is the radius of…2 mk
- Q24Differentiate between intrinsic and extrinsic semiconductors. OR Draw the circuit arrangement for studying the V-I…2 mk
- Q24Identify the part of electromagnetic spectrum which is: next to the lowest frequency end of the visible part of…2 mk
- Q24Draw energy band diagram for an n -type and p -type semiconductor at T>0 K.2 mk
- Q24Use Gauss's law to obtain the expression for electric field due to a uniformly charged infinite plane thin sheet.2 mk
- Q24Explain the roles of diffusion current and drift current in the formation of the depletion layer in a p-n junction…2 mk
- Q25Two coils C_1 and C_2 are placed close to each other. The magnetic flux φ_2 linked with the coil C_2 varies with the…2 mk
- Q25A point object in air is placed symmetrically at a distance of 60 cm in front of a concave spherical surface of…2 mk
- Q25Calculate the wavelength of the second line of Lyman series in a spectrum of hydrogen atom. (Take Rydberg constant, R=1…2 mk
- Q25Answer the following giving reasons: (i) A p-n junction diode is damaged by a strong current. (ii) Impurities are added…2 mk
- Q25Obtain an expression for electrostatic potential energy of a system of three charges q, 2 q and -3 q placed at the…2 mk
- Q25Draw a circuit diagram of a p-n junction diode in forward biasing, and reverse biasing. Draw the V-I characteristics…2 mk
- Q25Briefly explain how the diffusion and drift currents contribute to the formation of potential barrier in a p-n junction…2 mk
- Q25Two identical cells, each of emf E and internal resistance r, are connected with a load resistance R, first in series…2 mk
- Q25Explain the property of a p-n junction which makes it suitable for rectifying alternating voltages. Differentiate…2 mk
- Q26A plane wave-front propagating in a medium of refractive index ' μ_1 ' is incident on a plane surface making an angle…3 mk
- Q26A particle of mass m and charge q is accelerated through a potential difference V. Plot a graph of de Broglie…3 mk
- Q26A potential difference V is applied across a conductor of length l and uniform cross-section area A. How will the (i)…3 mk
- Q26A series RL circuit with R=10 Ω and L=(100/(π)) mH is connected to an ac source of voltage V=141 sin (100 π t), where V…3 mk
- Q26A plane wave-front propagating in a medium of refractive index ' μ_1 ' is incident on a plane surface making an angle…3 mk
- Q26Draw a plot showing the variation of potential energy of two nucleons as a function of distance between them. Identify…3 mk
- Q26Two circular loops A and B, each of radius 3 m, are placed coaxially at a distance of 4 m. They carry currents of 3 A…3 mk
- Q26Twelve negative charges of same magnitude are equally spaced and fixed on the circumference of a circle of radius R as…3 mk
- Q26An ac voltage v=v_m sin ω t(v_m=310 V. and.f=50 Hz) is connected to a pure capacitor of capacitance 15 μ F. Calculate…3 mk
- Q26A ray of light is refracted by a glass prism. Obtain an expression for the refractive index of the glass in terms of…3 mk
- Q26Two charged conducting spheres of radii a and b are connected to each other by a wire. Find the ratio of the electric…3 mk
- Q27Define current density and relaxation time. Derive an expression for resistivity of a conductor in terms of number…3 mk
- Q27A ray of light is incident on a glass prism of refractive index μ and refracting angle A. If it just suffers total…3 mk
- Q27An alternating current I=14 sin (100 π t) A passes through a series combination of a resistor of 30 Ω and an inductor…3 mk
- Q27What is meant by the term 'mutual inductance' of a pair of coils? Obtain an expression for the mutual inductance of two…3 mk
- Q27How does the resistance differ from impedance? With the help of a suitable phasor diagram, obtain an expression for…3 mk
- Q27A current of 1 A flows through a coil when it is connected across a DC battery of 100 V. If DC battery is replaced by…3 mk
- Q27(i) In diffraction due to a single slit, the phase difference between light waves reaching a point on the screen is 5…3 mk
- Q27An alternating voltage of 220 V is applied across a device X. A current of 0.22 A flows in the circuit and it lags…3 mk
- Q27The threshold wavelength for a metal is 3315. What should be the wavelength of light incident on the metal surface so…3 mk
- Q27A current carrying circular loop and a straight wire bent partly in the form of a semicircle are placed as shown in the…3 mk
- Q27The figure shows the variation of induced emf as a function of rate of change of current for two identical solenoids X…3 mk
- Q28A long solenoid of radius r consists of n turns per unit length. A current I=I_0 sin ω t flows in the solenoid. A coil…3 mk
- Q28A resistor of 30 Ω and a capacitor of 250/(π) μ F are connected in series to a 200 V, 50 Hz ac source. Calculate (i)…3 mk
- Q28The figure shows a rectangular conductor PQRS in which the arm PQ of length 10 cm and resistance 0 · 4 Ω is free to…3 mk
- Q28State the basic principle behind the working of an ac generator. Briefly describe its working and obtain the expression…3 mk
- Q28The primary coil having N_p turns of an ideal transformer is supplied with an alternating voltage V_p. Obtain an…3 mk
- Q28Three point charges Q_1(-15 μ C), Q_2(10 μ C) and Q_3(16 μ C) are located at (0 cm, 0 cm),(0 cm, 3 cm) and (4 cm, 3 cm)…3 mk
- Q28A series CR circuit with R=200 Ω and C=(50 / π) μ F is connected across an ac source of peak voltage ε_0=100 V and…3 mk
- Q28An ac source v=v_m sin ω t is connected across an ideal capacitor. Derive the expression for the (i) current flowing in…3 mk
- Q28The primary and the secondary coils of an ideal step-down transformer consist of 650 and 25 turns respectively. When…3 mk
- Q28Differentiate between 'impact parameter' and 'distance of closest approach' in alpha particle scattering experiment.…3 mk
- Q29Calculate the wavelength of de Broglie waves associated with a proton having (500/(1 · 673)) eV energy. How will the…3 mk
- Q29A rectangular loop of sides 25 cm and 20 cm is lying in x-y plane. It is subjected to a magnetic field B=(5 t^2+2 t+10)…3 mk
- Q29How does Einstein's photoelectric equation explain the emission of electrons from a metal surface? Explain briefly.…3 mk
- Q29Define critical angle for a given pair of media and total internal reflection. Obtain the relation between the critical…3 mk
- Q29Briefly describe how the current sensitivity of a moving coil galvanometer can be increased. A galvanometer shows full…3 mk
- Q29Two infinitely long parallel conductors A and B, separated by 2 cm, carry 6 A and 2 A currents in opposite directions…3 mk
- Q29Two cells of emf E_1 and E_2 and internal resistances r_1 and r_2 are connected in parallel, with their terminals of…3 mk
- Q29A potential difference V is applied across a conductor of length l and cross- sectional area A. Briefly explain how the…3 mk
- Q29Obtain a relation between the current flowing in a conductor and drift velocity of electrons in it. Hence, obtain Ohm's…3 mk
- Q30Two coplanar concentric circular loops of radii R and r(≪ R) are arranged coaxially. Obtain the expression for their…3 mk
- Q30A particle is associated with a de Broglie wave of wavelength 1.2 nm. The kinetic energy of the particle is made four…3 mk
- Q30(i) Prove that the nuclear density is same for all nuclei. (ii) Draw a plot of potential energy of a pair of nucleons…3 mk
- Q30Calculate the binding energy of an alpha particle in MeV. Given mass of a proton =1.007825 u mass of a neutron…3 mk
- Q30A resistor of 50 Ω, a capacitor of (25/(π)) μ F and an inductor of (4/(π)) H are connected in series across an ac…3 mk
- Q30A potential difference ' V ' is applied across a load resistor of resistance R. V and R can be varied. If the current…3 mk
- Q30Draw the energy level diagram for hydrogen atom. Mark the transitions corresponding to the series lying in the…3 mk
- Q30A 100 μ F capacitor is charged by a 12 V battery. How much electrostatic energy is stored by the capacitor? The…3 mk
- Q30A rectangular conductor MNPQ with a movable arm MN (resistance r ) is kept in a uniform magnetic field as shown in the…3 mk
- Q30Briefly explain Geiger-Marsden experiment. Show the variation of the number of particles scattered ( N ) with…3 mk
- Q30The figure shows de Broglie wavelength ( λ ) for two particles A and B having same charges but different masses as a…3 mk
- Q30(i) Differentiate between 'distance of closest approach' and 'impact parameter'. (ii) Determine the distance of closest…3 mk
- Q30(i) Write the limitations of Rutherford's model of atom. (ii) The wavelength of the second line of the Balmer series in…3 mk
- Q30(i) Distinguish between nuclear fission and fusion giving an example of each. (ii) Explain the release of energy in…3 mk
- Q31(i) Define electric flux and write its SI unit. (ii) Use Gauss' law to obtain the expression for the electric field due…5 mk
- Q31(i) Use Gauss' law to obtain an expression for the electric field due to an infinitely long thin straight wire with…5 mk
- Q31(i) State Coulomb's law in electrostatics and write it in vector form, for two charges. (ii) 'Gauss's law is based on…5 mk
- Q31(i) Explain how free electrons in a metal at constant temperature attain an average velocity under the action of an…5 mk
- Q32(i) (1) Write two points of difference between an interference pattern and a diffraction pattern. (2) Name any two…5 mk
- Q32(i) Define coefficient of self-induction. Obtain an expression for self-inductance of a long solenoid of length l, area…5 mk
- Q32Draw the circuit arrangement for studying V-I characteristics of a p-n junction diode in (i) forward biasing and (ii)…5 mk
- Q32(i) Write the principle and explain the working of a moving coil galvanometer. A galvanometer as such cannot be used to…5 mk
- Q32(i) State Biot-Savart's law for the magnetic field due to a current carrying element. Use this law to obtain an…5 mk
- Q32(i) Draw a ray diagram to show how the final image is formed at infinity in an astronomical refracting telescope.…5 mk
- Q33(i) Define mobility of electrons. Give its SI units. (ii) A steady current flows through a wire AB, as shown in the…5 mk
- Q33(i) Draw a ray diagram to show the working of a compound microscope. Obtain the expression for the total magnification…5 mk
- Q33(i) A germanium crystal is doped with antimony. With the help of energy-band diagram, explain how the conductivity of…5 mk
- Q33(i) Draw a ray diagram showing the formation of a real image of an object placed at a distance ' u ' in front of a…5 mk
- Q33(i) State Huygen's principle. With the help of a diagram, show how a plane wave is reflected from a surface. Hence…5 mk
- Q34Figure shows the variation of photoelectric current measured in a photo cell circuit as a function of the potential…4 mk
- Q34The following figure shows a circuit diagram. We can find the currents through and potential differences across…4 mk
- Q34A capacitor is a system of two conductors separated by an insulator. The two conductors have equal and opposite charges…4 mk
- Q34Consider the experimental set up shown in the figure. This jumping ring experiment is an outstanding demonstration of…4 mk
- Q34Electrostatics deals with the study of forces, fields and potentials arising from static charges. Force and electric…4 mk
- Q34A beam of electrons moving horizontally with a velocity of 3 × 10^7 m / s enters a region between two plates as shown…4 mk
- Q34A lens is a transparent optical medium bounded by two surfaces; at least one of which should be spherical. Considering…4 mk
- Q35Diffraction of light is bending of light around the corners of an object whose size is comparable with the wavelength…4 mk
- Q35Strontium titanate is a rare oxide - a natural mineral found in Siberia. It is used as a substitute for diamond because…4 mk
- Q35The lens maker's formula is useful to design lenses of desired focal lengths using surfaces of suitable radii of…4 mk
Other Physics years
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