Download 2019 physic all question papers pdf
Central boards of secondry education held physic paper in 2019 in various centres.
all set of those physic paper is given in below list and all this paper will very helpfull for 12th students of science stream.

you can download all physic paper of 2019 without any problem.
direct download link  is given in below list.

                                     



SOME IMPORTANT QUESTION.

1.Draw equipotential surfaces for an electric dipole. 

2. A proton is accelerated through a potential difference V, subjected to a  uniform magnetic field acting normal to the velocity of the proton. If the  potential difference is doubled, how will the radius of the circular path described by the proton in the magnetic field change ?

3.The magnetic susceptibility of magnesium at 300 K is 1·2 * 105. At what  temperature will its magnetic susceptibility become 1·44 * 105 ?

4The magnetic susceptibility x of a given material is – 0·5. Identify the  magnetic material.

5.Which part of the electromagnetic spectrum is used in RADAR ? Give its  frequency range.

6.How are electromagnetic waves produced by accelerating charges ? 
        
7.A capacitor made of two parallel plates, each of area ‘A’ and separation ‘d’ is charged by an external dc source. Show that during charging, the  displacement current inside the capacitor is the same as the current  charging the capacitor.

8.A photon and a proton have the same de-Broglie wavelength . Prove  that the energy of the photon is (2mc/h) times the kinetic energy of the  proton.

9Write the relation between the height of a TV antenna and the maximum  range up to which signals transmitted by the antenna can be received.  How is this expression modified in the case of line of sight communication  by space waves ? In which range of frequencies, is this mode of  communication used ? 

10.Under which conditions can a rainbow be observed ? Distinguish between  a primary and a secondary rainbow. 

11.Explain the following : 
(a) Sky appears blue.
(b) The Sun appears reddish at (i) sunset, (ii) sunrise.

12.Draw a labelled diagram of cyclotron. Explain its working principle.  Show that cyclotron frequency is independent of the speed and radius of the orbit. 

13.(a) Derive, with the help of a diagram, the expression for the magnetic  field inside a very long solenoid having n turns per unit length  carrying a current I. 
(b) How is a toroid different from a solenoid ? 

14.Prove that the magnetic moment of the electron revolving around a  nucleus in an orbit of radius r with orbital speed v is equal to evr/2. Hence using Bohr’s postulate of quantization of angular momentum,  deduce the expression for the magnetic moment of hydrogen atom in the  ground state.

15.A photon emitted during the de-excitation of electron from a state n to  the first excited state in a hydrogen atom, irradiates a metallic cathode of  work function 2 eV, in a photo cell, with a stopping potential of 0·55 V. Obtain the value of the quantum number of the state n. 

16.A hydrogen atom in the ground state is excited by an electron beam of  12·5 eV energy. Find out the maximum number of lines emitted by the  atom from its excited state. 

17.Draw the ray diagram of an astronomical telescope showing image  formation in the normal adjustment position. Write the expression for its  magnifying power. 

18.Draw a labelled ray diagram to show image formation by a compound  microscope and write the expression for its resolving power.

19(a) State the working principle of a meter bridge used to measure an unknown resistance. 
 (b) Give reason 
 (i) why the connections between the resistors in a metre bridge are made of thick copper strips,
 (ii) why is it generally preferred to obtain the balance length near the mid-point of the bridge wire.

20.Explain, with the help of a diagram, how plane polarized light can be produced by scattering of light from the Sun. Two polaroids P1 and P2 are placed with their pass axes perpendicular to each other. Unpolarised light of intensity I is incident on P1 . A third polaroid P3 is kept between P1 and P2 such that its pass axis makes an angle of 45 with that of P1 . Calculate the intensity of light transmitted through P1 , P2 and P3 . 

21.(a) Why cannot the phenomenon of interference be observed by illuminating two pin holes with two sodium lamps ? 
(b) Two monochromatic waves having displacements y1 = a cos omega t and y2 = a cos (omega t + fie) from two coherent sources interfere to produce an interference pattern. Derive the expression for the resultant intensity and obtain the conditions for constructive and destructive interference. 
(c) Two wavelengths 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. If the distance between the slit and the screen is 1·5 m, calculate the separation between the positions of the second maxima of diffraction pattern obtained in the two cases.

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