This document contains 11 unsolved physics problems from the 1992 IIT JEE past paper. The problems cover topics like moments of inertia, forces on liquids in rotating tubes, motion in circular paths, harmonic oscillations, Maxwell distribution of velocities in gases, photoelectric effect, transistor circuits, refraction, electric fields, hexagonal arrangements of point charges, resolving power of microscopes, speed of X-rays, Bohr model of the hydrogen atom, and a nuclear process. The document provides the questions and statements to be completed but does not show the solutions.

1. IIT JEE –Past papersPHYSICS- UNSOLVED PAPER - 1992

2. SECTION – ISingle Correct Answer TypeIn each part of this question, a statement is followed by four alternatives. In each part, one or more alternative(s) is (are) correct. Select the correct alternative(s) in each case and write down the corresponding letter(s) a, b, c, d in your answer book against the sub-question number. In your answers, the sequence of the sub-questions should be the same as in the question paper. For each sub-question, marks will be awarded only if all the correct alternatives are written.

3. 01ProblemThe moment of inertia of a thin square plate ABCD, Fig. 1992.1, of uniform thickness about an axis passing through the centre O and perpendicular to the plane of the plate is Where I1, I2, I3 and I4 are respectively the moments of inertia about axes 1, nd 4 which are in the plane of the plate.I1 + I2 I3 + I4I1 + I3I1 + I2 + I3 + I4

4. Problem02A tube of length L is filled completely with an incompressible liquid of mass M and closed at both the ends. The tube is then rotated in a horizontal plane about one of its ends with a uniform angular velocity . The force exerted by the liquid at the other end is M 2L/2M 2LM 2L/4M 2L2/2

5. Problem03A car is moving in a circular horizontal track of radius 10 m with a constant speed of 10 m/s. A plumb bob is suspended from the roof of the car by a light rigid rod of length 1.00 m. The angle made by the rod with the track is Zero300450600

6. Problem04A highly rigid cubical block A of small mass M and side L is fixed rigidly no to another cubical block B of the same dimensions and of low modulus of rigidity such that the lower face of A completely covers the upper face of B. The lower face of B is rigidly held on a horizontal surface. A small force F is applied perpendicular to one of the side face of A. After the force is withdrawn, block A executes small oscillations the time period of which is given by a.b. c. d.

7. Problem05Three closed vessels A, B and C are at the same temperature T and contain gases which obey the Maxwell an distribution of velocities. Vessel A contains only O2, B only N2 and C a mixture of equal quantities Of O2 and N2. If the average speed of the O2 molecules in vessel A is V1, that of the N2 molecules in vessel B is V2, the average speed of the O2 molecules in vessel C is(V1 + V2)/2V1(V1 V2)1/2

8. Problem06The displacement y of particle executing periodic motion is given byThe expression may be considered to be a result of the superposition ofTwo ThreeFour Five Independent harmonic motions

9. Problem07A planet is observed by an astronomical refracting telescope having an objective of focal length 16 m and an eyepiece of focal length 2 cm. The distance between the objective and the eyepiece is 16.02 m.The angular magnification of the planet is –800.The image of the planet is inverted. The objective is larger than the eyepiece

10. Problem08Two identical thin rings, each of radius R, are coaxially placed a distance R apart, If Q1 and Q2 are respectively the charges uniformly spread on the two rings, the work done in moving a charge q form the centre of one ring to that of the other is Zeroc.d.

11. Problem09When a monochromatic point source of light is at a distance of 0.2 m from a photoelectric cell, the cut-off voltage and the saturation current are respectively 0.6 volt and 18.0 m A. If the same source is placed 0.6 m away from the photoelectric cell, then The stopping potential will be 0.2 voltThe stopping potential will be 0.6 voltThe saturation current will be 6.0 m AThe saturation current will be 2.0 m A.

12. Problem10In an n-p-n transistor circuit, the collector current is 10mA. If 90% of the electrons emitted reach the collector, The emitter current will be 9 mAThe emitter current will be 11mAThe base current will be 1 mAThe base current will be –1mA.

13. SECTION – IIFill in the blanksA blank to be filled appears in each of the following statements. Write, in your answer book, the sub-question number and write down against it your answer corresponding to each blank. In your answers, the sequence of the sub-questions should be the same as given in the question paper.

14. 01ProblemA substance of mass M requires a power input of P to remain in the molten state at its melting point. When the power source is turned off, the sample completely solidifies in time t. The latent heat of fusion of the substance is…………

15. Problem02A cylindrical resonance tube open at both ends has a fundamental frequency F in air. Half of the length of the tube is dipped vertically in water. The fundamental frequency of the air column now is ……………

16. Problem03A ray of light undergoes deviation of 300 when incident on an equilateral prism of refractive index The angle made by the ray inside the prism with the base of the prism is ……….

17. Problem04If and are, respectively, the electric permittivity and magnetic permeability of free space, and the corresponding quantities in a medium, the index of refraction of the medium in terms of the above parameters is …………

18. Problem05The electric potential V at any point x, y, z in space is given by V = 4x2 volt/meter2. The electric field at the point (1 m, 0, 2 m) is ………V/m.

19. Problem06Five points charge, each of vale +q, are placed on five vertices of a regular hexagon of side L. the magnitude of the force on a point charge of value –q placed at the centre of the hexagon is ………. Newton's.

20. Problem07The resolving power of an electronic microscope is higher than that of a optical microscope because the wavelength of electrons is ……..than the wavelength of visible length.

21. Problem08In an X-ray tube, electrons accelerated through a potential difference of 15,000 volts strike a copper target. The speed of the emitted X-rays inside the tube is …….m/s.

22. Problem09In the Bohr model of the hydrogen atom, the ratio of the kinetic energy to the total energy of the electron in a quantum state n is …………

23. Problem10In the nuclear process

24. Problem11X stands for …………….

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