Physics Classes

Category: 12th Assignments

  • Most important numerical of electrostatics

    Important numerical of electrostatics  ( Top 12 )

    This assignment contain top 12 important numerical  of electrostatics , chapter 1 and 2 (unit-1). Students preparing for 12th board examination included all states and ICSE board ( even students preparing for JEE/NEET) must solve these numerical.

    1. (i)Two point charges 4Q and Q are separated by 1m in air at what point on the line joining the two charges the electric field intensity is zero. (ii) Two identical metallic sphere A and B having charges +4Q and -10Q are kept at a certain distance apart . A third identical uncharged sphere C is first placed in contact with sphere  A and then with sphere B . Spheres A and B are then brought in contact and then separated . Find the charges on the sphere A and B . 

    To download the complete assignment pdf click here-

    2. (i) Calculate the amount of work done in turning an electric dipole of dipole moment 3×108 C-m from its position of unstable equilibrium to stable equilibrium, in a uniform electric field of intensity 103N/c. (ii)The electric field components due to a charge inside the cube of side 0.1m are shown below      Ex=αx   ,  where α =500N/C-m EY=0,EZ=0

    Calculate (a) The flux through the cube (b)the charge inside the cube

    3.(a) A uniformly charged conducting sphere of 2.5 m in diameter has a surface charge density of 100µC/m2 . Calculate the  (a) charge on the surface  and (b)Total electric flux through the surface. (b)Two large, thin metal plates are parallel and close to each other.  On their inner faces, the plates have surface charges densities of opposite signs and of magnitude 17.0 x 10-22 C/m2.   What is electric field strength E:  (a) in the outer region of the first plate, (b) in the outer region of the second plate, and (c)  between the plates?

    TO DOWNLOAD THE COMLETE ASSIGNMENT CLICK HERE-

  • Assignment current electricity

    This assignment contain all important questions of chapter current electricity.

    1. How does the drift velocity of electrons in a metallic conductor very with increase in temperature ?                               2.The metallic conductor is at a temperature  θ1 .The temperature of the metallic conductor is increased to θ2 How will the product of its resistivity andconductivitychange?                                                                                 3. A cell of e.m.f. 2 V and internal resistance 0.1 Ω is connected to a 3.9 Ω external resistance .What will be the p.d. across the terminals of the cell 4.Nichrome and copper wires of the same length and same radius are connected in series .Current I is passed through them .Why does the nichrome wire get heated first ?                                       5. Sate the condition in witch terminal voltage across a secondary cell is equal to its e.m.f.                                                                 6. Two bulbs whose resistances are in the ratio of 1 ; 2, are connected in parallel to a source of constant voltage . What will be the ratio of power dissipation in these?                                                                                                            7. A toaster produces more heat than a light bulb when connected in parallel to the 220 V mains. Which of the two has greater resistance ?      

    TO DOWNLOAD THE ASSIGNMENT CLICK HERE-

  • Test magnetism and electromagnetic induction

    There are 20 questions in the question paper , in which 14 are objective, (1 marker) and other 6 are subjective which carry 2 marks each .

    This question paper covers the chapter magnetism and electromagnetic induction . It is just for the practice the questions of the chapters magnetism and electromagnetic induction.

    1. Define the term magnetic moment of a current loop . Write the expression for the magnetic moment when an electron revolve at speed v around the   orbit of radius r in hydrogen atom .

     2 .  Define magnetic susceptibility of the materials . Name two elements , one having positive and other having negative susceptibility . what does negative susceptibility signify ?

      3. A bar magnet of magnetic moment M is aligned parallel to the direction of a uniform magnetic field B. What is the work done to turn the magnet, so as the align its magnetic moment  (i) Opposite to the field direction  (ii) Normal to the field direction?

    4. Two circular coils one of small radius r and other of very large radius R are placed coaxially with center coinciding. Obtain the mutual inductance of the arrangement.

    To download the complete question paper click here –

  • Very important numerical of magnetic effect of current

    Very important numerical of magnetic effect of current

    This blog contain very important numerical of magnetic effect of current. There are 10 numerical based on this chapter. It is not necessary that questions will be asked from this blog same as given questions, but these questions will help you to improve your numerical skill . Students preparing for class 12th board exam must solve these questions, i am sure it will help you to improve and sole numerical question of this chapter.

    1. Two wires A and B have the same length equal to 44cm . and carry a current of 10A each . Wire A is bent in circle and B as a square .(a) obtain the magnetic field by both the coils at the center ,(b) which has more field at their centre?

    2. A straight long thick  wire of uniform cross-section ( radius  r=10cm ) carries current 10A through it . Calculate the ratio of magnetic field at a point  r/2 above the surface and a point r/2 below the surface. What is the maximum field due to this current carrying wire?

    To download the 10 very important numerical-ch-4 click hereDownload

  • Practice Test ELECTROSTATICS

    This test paper is useful for the students studying in class 12th.Chapter included in this paper is only electrostatics ( Both chapter-1 and chapter-2 of NCERT).

    .  State Gauss’s law . Using this law derive an expression for the electric field due to a (1) uniformly charged infinite charged plane sheet, (2) charged spherical shell, (3) infinite long charged wire  of linear charge density λ.                                                                                                                                   

     7. S1 and S2 are two hollow concentric spheres enclosing charges Q and 2Q respectively as shown in fig. (1) what is the ratio of electric flux through S1­ and S2 . (2) How will the electric flux through S1 chenges if a medium of dielectric constant  5 is introduced in the space inside S1 in place of air.

    TO DOWNLOAD CLICK HERE

  • NCERT PHYSICS SOLUTION ( CLASS -11th )

    This blog contain class 11th physics NCERT solution , it will help the students to solve all chapters NCERT solution . This blog contain chapter wise solution . This blog also contain the all additional questions , which is not available in current book provided by CBSE . But I considered these questions are important for JEE and NEET .

  • AI or Artificial intelligence

    In this blog we will know what is AI or artificial intelligence ?

    AI or artificial intelligence ,

    It refers to the simulation of human intelligence in machines. These machines are programmed to think , learn , Do  analysis  and take decisions as a man does .

    AI can used in the following forms-

    1. Machine learning (ML) ; In this form machine learn from data given to it and improve it with time without clearly  programmed .

    2.Natural Language Processing (NLP): Enables machines to understand and respond to human language.

    3.Computer Vision: Allows machines to interpret and analyze visual information from the world.

    3. Robotics: Combines AI with physical machines to perform tasks in the real world.

    In short, AI helps machines do tasks that normally require human intelligence, such as recognizing speech, playing games, recommending products, or even driving cars.

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  • Test eletric chargs and fileld

    Test eletric chargs and fileld

    This test paper based on the topic Electric charges and field,(chapter -1 CBSE ). This test paper contains objective, assertion-reason ,case study based questions also, provided by Physics classes by Nayan jha.

    PHYSICS CLASSES BY NAYAN JHA

                                                       Test class 12th

    1.Two small identical sphere having charges +10μC attract each other with a force of F newton. If they are kept in contact and then separated by the same distance, the new force between them is: (a) F/6      (b) 16F      (c) 16F/9        (d) 9F                   

    2.An electric dipole is placed in a non-uniform electric field. Then net:

    • force experienced is zero while torque is not zero
    • force experienced is zero and torque is also zero
    • both force and torque are not zero
    • force experienced is not zero while torque is zero                                     

    3.Electric charges q , q, -2q are placed at the corners of an equilateral triangle ABC of side l. The magnitude of electric dipole moment of the system is:

    • (a)ql            (b) 2ql                      (c) √3ql                      (d) 4ql               

    4.Eight dipoles of charges of magnitude e are placed inside a cube. The total electric flux coming out of the cube will be: (a) 8e/ε0    (b) 16e/ε0   (c) e/ε0     (d) zero            

    5.The ratio of electric fields on the axis and at equator of an electric dipole will be:

    • (a)1 : 1     (b) 2 : 1         (c) 4 : 1        (d) 1 : 4                                

    6.Two point charges exert on each other a force F when they are placed r distance apart in air. When they are placed R distance apart in a medium of dielectric constant K, they exert the same force. The distance R equals: (a)r/√K                            (b) r/K                       (c) rK                        (d) r√K                                                                                                                                         To download the complete test paper click on the link given below-

    TEST-1-CLASS12TH-22-23Download

    To download the another test paper of this chapter click here-

    TEST-2 ELECTROSTATICSDownload

    Test-3-electrostaticsDownload

  • Very important numericals physics( term-2)

    Important numericals physics term-2 (CBSE)

    1. What is apparent position of the object below a rectangular block of glass 6cm thick , if a layer of water 4cm thick is on the top of the glass ? Refractive index of glass and water with respect to air is 3/2 and 4/3 respectively.
    2. A screen is placed 100cm from an object  . The image of the object on the screen is formed by a convex lens at two different locations , separated by distance 20cm . calculate the focal length of the lens used.
    3. You are given three lenses  L1 , L2,L3 each of focal length 10cm . an object is kept at 15cm in front of L1  ,  as shown in fig. the final image is formed at the focus of L3 find the separation between the lenses.
    • 4. A convex lens made up of glass of refractive index 1.5 is  dipped  , in turn ,in (a) a medium of refractive index 1.65 (b)   ) a medium of refractive index 1.33.Will it behave like converging or diverging lens in two cases, explain how focal length changes in two cases .
    • 5.Three rays  red  , green and blue are incident on a right angled prism ABC at face AB the refractive indices of the material  of the prism for red, green ,and blue are 1.39,1.44, and 1.47 respectively . Out of the three which colour of ray emerge out of face AC. Trace the path of the three rays after passing through AB.
    • 6. State the conditions under which total internal reflection occurs . one face of a prism with a refracting angle of 30 , is coated with silver . A ray incident on  another face at an angle of 45 is refracted and reflected from the silver coated face and retrace its path. Find the refractive index of the material of the prism.
    • 7. Find the position of the image formed by the lens combination given in figure   
    • 8. A diverging lens of focal length f cut into two identical parts ,each forming a plano- convex lens what is the focal length of each part. How the focal length of the lens changes if it bisected axially?
    • 9. The image of a needle placed 45cm from a lens is formed on a screen placed 90 cm on the other side of lens. Find displacement of image if object is moved 5cm away from lens.
    • 10. A small bulb is placed at  the bottom of a tank containing water to a depth of 80 cm . what is the area of the surface of water through which light of the bulb can emerge out ?Refractive index of water is 1.33 consider the bulb to be a point source.
    •  11. Yellow light of wavelength λ= 6000 A illuminate a single slit of width 1 x 10-4 m calculate (i) the distance between two dark lines on either side of the central maximum when the diffraction pattern is on screen kept 1.5 m away from the slits , (ii) the angular spread of the first diffraction minima .

       Ans- 1.8 cm , 6x 10-3 rad . 12. Two wavelength of sodium light 590 nm are used in turn , to study the diffraction taking place at the single slit of aperture  2x 10-4 m . The distance between the slits and the screen is 1.5 m . Calculate the separation between the position of first maxima of the diffraction pattern obtained in the two cases .

      Ans-6.75×10-5m . 13. (a) In a single slit diffraction , a slit of width d is illuminated by red light of wavelength 650 nm . For what value of  d will (i) the first minimum fall at an angle of diffraction of 300 , and   (ii) the first maximum fall at an angle of diffraction of 300 ? 

      (b) Why does the intensity of secondary maximum becomes less as compared to the central maximum .

         Ans- 1.3 x10-6 m , 1.95×10 ‑6‑ m 14. A monochromatic light of wavelength 500 nm is incident normally on a single slit of width 0.2 mm to produce a diffraction pattern . Find the angular width of the central maximum obtained on the screen . Also estimate the number of fringes obtained in YDSE with fringe width 0.5 mm , which can be accommodate within the region of total angular spread of the central maximum due to single slit .            Ans- ϴ=0 to 2.5×10-3 ; n=D/2 ;D+1 15.A beam of light consisting of two wavelength 800nm and 600 nm is used to obtain the interference pattern in YDSE on a screen placed 1.4 m away . If the two slits are separated by 0.28mm , calculate the least distance from the central bright maximum where the bright fringes of the two wavelengths coincide . Ans- n=3 ; 1.2 cm . 16. In YDSE using monochromatic light of wavelength λ, the intensity of light at a point on the screen where path difference is λ is K units . Find out the intensity of light of light at a point where path- difference is λ/3 . 17. The ratio of the intensity at minima to the maxima in YDSE is 9:25 , find the ratio of the width of the two slits , also find the ratio of amplitude .   Ans- 16:1 . 18. Two wavelength of sodium light of 590 nm and 596 nm are used in turn to study the diffraction taking place at a single slit of aperture 2×10-6 m . The distance between the slit and the screen is 1.5 m . Calculate separation between the position of first maxima and of the diffraction pattern obtained in the two cases .

     Ans- 6.75 nm .

    19. The electron in a given Bohr orbit has a total energy of -1.5Ev. calculate its(i) kinetic energy(ii)potential energy (iii) wavelength of the radiation emitted , when this electron makes a transition to the ground state.

    20. The energy of an electron in the ground state of hydrogen atom is -13.6 Ev. (i) what does the negative sign signify ? (ii)how much energy is required to take an electron in this atom from the ground state to the first exited state?

    21. The ground state energy of hydrogen atom is  -13.6 eV.  ( I ) What is the potential energy of an electron in the third exited state? (ii) what will be the maximum and minimum wavelength of the emitted  radiation of Lyman series of hydrogen spectrum.

    22. The energy level diagram  of an element is given below . identify using necessary calculations , which transition corresponds to the emission of the spectral line of wavelength 102.7 nm . which transition corresponds to the emission of radiation of maximum wavelength?  

    .

    23.The first line of Lyman series in hydrogen spectrum has a wavelength of 1220 Å. Calculate the wavelength of the second member of the series.

    24. A nucleus at rest splits up into two parts with velocity ratio 2 : 1 calculate the ratio of their radii of the ratio the two nuclear fragments.

    25.The ground state energy of electron in hydrogen atom is – 13.6 eV. Find the kinetic energy and potential energy of the electron in (i) ground state (ii) first excited state.

  • Physics Sample paper class12th(term-2)

    Sample paper -1

                                                            Class 12th

                                                        Physics (Theory)   Term-2

                                    

    M.M: 35                                                                                                             TIME-2Hrs

     Here Physics classes by Nayan jha providing CBSE Term-2 Physics sample paper .

    There are 12 questions in all and all questions are compulsory.

     This question paper consists of three section A,B and C.

    SECTION A has three questions of two marks each , 

    SECFTION- B there are eight questions carrying three marks each and

    SECTION- C is case study based questions of five marks.

    There is no overall choice . However , an internal choice has been provided.

    Uses of calculator is not allowed.

    SECTION-A

    1. Find the ratio of energies of photons produced due to transition of electron of hydrogen atom from its (i) Second permitted energy level to the first level and, (ii) the highest permitted energy level .

    Or,

    The ground state energy of hydrogen atom is -13.6eV. What is the kinetic and potential energy of electron in this orbit.

    2. Draw the circuit diagram showing the biasing of an LED . State the factor which controls (i) Wavelength of light (ii) intensity of light emitted by the diode.

    3. Write the photoelectric equations of Einstein . Write two basic features of photon picture of electromagnetic radiation on which Einstein’s photoelectric equation is based.

    SECTION-B

    4. Draw V-I characteristics of p-n junction diode (i) When diode is reversed bias and (ii) when diode is forward biased . Explain why the current under reverse bias is almost independent of the applied voltage up to the critical voltage?

    5.State the necessary conditions for producing total internal reflection of light. Draw the diagram to show how specially designed prism make use of T.I.R to obtained inverted image of the object by deviating rays (i) through 900 and (ii) Through 1800.

    Or,

    Three rays of light red , green and blue is fall normally on one of the equal side of an isosceles right angled prism . The refractive index of these rays are 1.39,1.44,1.47 respectively . Find which of these rays get internally reflected from diagonal side . Trace the path of rays . Justify your answer with necessary conditions.

    6. Using Bohr postulates for hydrogen atom , show that the total energy of the electron in the stationary states can be expressed as the sum of kinetic energy(K) and potential energy (U)  , where K=-2U. hence , deduce the expression for the total energy in the nth energy level of hydrogen atom .

    Or,

     Draw a labelled diagram of alpha particle scattering experiment. Give Rutherford observations and  discuss the significance of this experiment .

    7. How the size of nuclei is experimentally determined ? write the relation between the radius and mass number of the nucleus . show that the density of the nucleus is independent of its mass number. Two nuclei of mass number in the ratio 27:125. What is the ratio of their nuclear radius and , ratio of their densities.

    Or,

    Draw the binding energy per nucleon curve . using the curve state clearly how the release in energy in the process of nuclear fission and nuclear fusion can be explained.

    8. An electron of mass m  and charge q is accelerated from rest through a potential difference V  , obtain the expression for the de-Broglie  wavelength  associated with it . if electron and proton are moving with the same K.E. , which one of them will have a large De-Broglie wavelength associated with it ? give reason .

    9. I n a single slit diffraction experiment , deduce the conditions for the central maximum and secondary maxima/minima observed in diffraction pattern . Also explain why the secondary maxima go on becoming weaker in intensity as the order increases. Haw does the width of the slit affected the size of the central bright fringe?

    10. Using Young’s double slit experiment obtain the conditions for gating bright and dark fringes  also derive the expression for the fringe width.  Also write the effect on fringe width when(I)Distance between slits increases/decreases (II) Distance between slits and the screen increases/decreases(III) Monochromatic light replaced  by white light,(IV) One of slit is closed and (V) entire experimental apparatus is immersed in a liquid.

    11.  (i) Which segment of electromagnetic waves has highest frequency? How are these waves produced? Give one use of these waves.

    (ii) Which EM waves lie near the high frequency end of visible part of EM spectrum? Give its one use. In what way this component of light has harmful effects on humans?

                Section-C

    12.

     Power of a lens-

    Power (P) of a lens is given as the reciprocal of focal length (P=1/f)where f should be in meter and P is in Diopter . for convex power is positive and concave power is –ve. When two or more lenses are kept in contact then power of the combined lens is given as P= P1 + P2+P3 …….

    (I) A convex and a concave lens is separated by distance d are then put in contact then the focal length of the combination  (a) becomes 0 (b) remain the same (iii) decreases (iv)increases.

    (ii)The two lenses of power +1.5D and +1.0D are placed in contact then the effective power of the combination will be (a)2.5D (b)1.5 D (c) 0.5D (d)3.25D .

    (iii) If the power of the lens is 5D then what is the focal length of the lens?(a)10cm (b) 20cm (c)15cm (d) 5cm

    (iv)Two thin lens of focal length +10cm and -5cm are kept in contact , the power of the combination is ? (a)-10D (b)-20D (c)10D (d)15D .

    (v)A convex lens of focal length 25cm is placed coaxially in contact with a concave lens of focal length 20cm the system will be ; (a) converging in nature (ii) diverging in nature (c) can be converging or diverging (d) None of the above.

    Samle-paper2-22-12thDownload

    samplpaper-3.pdf