This document contains 31 physics problems from an unsolved IIT JEE past paper from 2000. The problems cover topics in mechanics, electromagnetism, optics, and thermodynamics. Multiple choice options are provided for each problem, but no solutions are given. The document introduces the section as containing multiple choice questions with a single correct answer for each problem.

1. IIT JEE –Past papersPHYSICS - UNSOLVED PAPER - 2000

2. SECTION – ISingle Correct Answer TypeThis section contains multiple choice questions. Each question has four choices (A), (B), (C) and (D) out of which ONLY ONE is correct.01ProblemIn a compound microscope,the intermediate image is virtual,erect and magnifiedreal,erect and magnified.real,inverted and magnifiedvirtual,erect and reduced.

3. Problem02A ball is dropped vertically from a height d/2.Neglecting subsequent motion and air resistance, its velocity varies with the heigh h above the ground as

4. Problem03Two vibrating strings of the same material but lengths L and 2L have radii 2r and r, respectively. They are stretched under the same tension. Both the strings vibrate in their fundamental modes, the one of length L with frequency and the other with frequency .The ratio is given by2481

5. Problem04Two monatomic ideal 1 and 2 of molecular masses respectively are enclosed in separate containers kept at the same temperature. The ratio of the speed of sound in gas 1 to that in gas 2 is given bya.b.c.d.

6. Problem05A coil of wire having finite inductance and resistance has a conducting ring placed coaxially within it. The coil is connected to a batttery at time t=0 ,so that a time-depecdent current starts flowing through the coil. If is the current induced in the ring,and is the magnetic field at the axis of the coil due to ,then as a function of time (t > 0),the product increases with timedecreases with timedoes not vary with timepasses through a maximum.

7. Problem06The electron in a hydrogen atom makes a transition from an excited state to the ground state. Which of the following statements is true ?Its kinetic energy increases and its potential and total energies decrease.Its kinetic energy decreases, potential energy increases and its total energy remains the same.Its kinetic and total energies decrease and its potential energy increases.Its kinetic, potential and total energies decrease.

8. Problem07The dimension of ( : permittivity of free space; E:electric field) isa.b.c.d.

9. 08ProblemAn ideal gas is initially at temperature T and volume V. Its volume is increased by due to an increase in temperature , pressure remaining constant. The quantity varies with temperature asa.b.c.d.

10. Problem09A hollow double concave lens is made of very thin transparent material.It can be filled with air or either of two liquids having refractive indices ,respectively . The lens will diverge a parallel beam of light if it is filled withair and placed in airair and immersed in and immersed in and immersed in

11. Problem10An ionized gas contains both positive and negative ions. If it is subjected simultaneously to an electric field along the +x direction and a magnetic field along the +z direction, thenpositive ions deflect towards +y direction and negative ions towards –y direction.all ions deflect towards +y direction.all ions deflect towards –y direction.positive ions deflect towards –y direction and negative ions towards +y direction.

12. Problem11A uniform but time-varying magnetic field B(t) exists in a circular region of radius a and is directed into the plane of the paper, as shown .The magnitude of the induced electric field at point p at a distance r from the centre of the circular regionis zerodecreases as increases as decreases as

13. 12ProblemA long horizontal rod has a bead which can slide along its length, and initially placed at a distance L from one end A of the rod. The rod is set in angular motion about A with constant angular acceleration .If the coefficient of friction between the rod and the bead is and gravity is neglected, then the time after which the bead starts slipping isinfinitesimal

14. Problem13Imagine an atom made up of a proton and a hypothetical particle of souble the mass of the electron but having the same charge as the electron. Apply the Bohr atom model and consider all possible transitions of this hypothetical particle to the first excited level. The longest wavelength photon that will be emitted has wavelength (given in terms of the Rydberg constant R for the hydrogen atom ) equal to9/(5R)36/(5R)18/(5R)4/R

15. Problem14An equilateral triangle ABC formed from a uniform wire has two small identical beads initially located at A. The triangle is set rotating about the vertical axis AO. Then the beads are released form rest simultaneously and allowed to slide down ,one along AB and the other along AC as shown. Neglecting frictional effects, the quantites that are conserved as the beads slide down, areangular velocity and total energy (kinetic and potential)total angular momentum and total energy.angular velocity and moment of inertia about the axis of rotationtotal angular momentum and moment of inertaablut the axis os rotation.

16. Problem15A train moves towards a stationary observer with speed 34m/s. The train sounds a whistle and its frequency registered by the observer is .If the train’s speed is reduced to 17 m/s, the frequency registered is .If the speed of sound is 340 m/s then the ratio is18/191/2219/18

17. Problem16The period of oscillation of a simple pendulum of length L suspended from the roof of a vehicle which moves without friction down an inclined plane of inclination ,is given bya.b.c.d.

18. 17ProblemA block of ice at -10 is slowly heated and converted to steam at 100 .Which of the following curves represents the phenomenon qualitatively?a.b.c.d.

19. Problem18A particle of charge q and mass m moves in a circular orbit of radius r with angular speed .The ratio of the magnitude of its magnetic moment to that of its angular momentum depends ona.b.c.d.

20. Problem19A point source of light B is placed at a distance L in front of the centre of a mirror of width d hung vertically on a wall.A man walks in front of the mirror along a line parallel to the mirror at a distance 2L from it as shown .The greatest distance over which he can see the image of the light source in the mirror is d/2d2d3d

21. Problem20Three charges are placed at the vertices of a right-angled isoceles triangle as shown .The net electrostatic energy of the configuration is zero is is equal toa.b.c.d.

22. Problem21A large open tank has two holes in the wall. One is square hole of side L at a depth y from the top and the other is a circular hole of radius R at a depth 4y from the top. When the tank is completely filled with water, the quantities of water flowing out per second from both holes are the same. Then, R is equal toa.b.c.d.

23. Problem22A wind-powered generator converts wind energy into electrical energy, Assume that the generator converts a fixed fraction of the wind energy intercepted by its blades into electrical energy .For wind speed ,the electrical power output will be proportional toa.b.c.d.

24. Problem23Two long parallel wires are at a distance 2d apart. They carry steady equal currents flowing out of the plane of the paper, as shown .The variation of the magnetic field B along the line XX’ is given bya.b.c.d.

25. Problem24Electrons with energy 80 keV are incident on the tungsten target of an X-rays tube.K shell electrons of tungsten have -72.5keV energy.X-rays emitted by the tube contain onlya continuous X-ray spectrum(Bremsstrahlung) with a minimum wavelength of a continuous X-ray spectrum (Bremsstrahlung) with all wavelengths.the characteristic X-ray spectrum of tungstena continuous X-ray spectrum(Bremsstrahlung)with a minimum wavelength of and the characteristic X-rays spectrum of tungsten.

26. Problem25A diverging beam of light from a point source S having divergence angle ,falls symmetrically on a glass slab as shown .The angles of incidence of the two extreme rays are equal. If the thickness of the glass slab is and the refractive index ,then the divergence angle of the emergent beam isZero

27. Problem26A rectangular glass slab ABCD of refractive index ,is immersed in water of refractive index . A rey of light is incident at the surface AB of the slab as shown .The maximum value of the angle of incidence ,such that the ray comes out only from the other surface a.b.c.d.

28. Problem27A thin wire of length L and uniform linear mass density is bent into a circular loop with centre at O as shown .The moment of inertia of the loop about the axis XX’ isa.b.c.d.

29. Problem28An infinitely long conductor PQR is bent to form a right angle as shown. A current flows through PQR .The magnetic field due to this current at the point M is .Now ,another infinitely long straight conductor QS is connected at Q so that the current is in QR as well as in QS, the current in PQ remaining unchanged. The magnetic field at M is now .The ratio is given by1/212/32

30. Problem29A cubical block of side L rests on a rough horizontal surface with coefficient of friction .A horizontal force F is applied on the block as shown .If the coefficient of friction is sufficiently high so that the block does not slide before toppling ,the minimum force required to topple the block isinfinitesimal

31. Problem30A parallel plate capacitor of area A, plate separation d and capacitance C is filled with three different dielectric materials having dielectric materials having dielectric constants as shown .If a single dielectric material is to be used to have the same capacitance C in this capacitor, then its dielectric constant k is given by a.b.c.d.

32. Problem31A monatomic ideal gas, initially at temperate ,is enclosed in a cylinder fitted with a frictionless position. The gas is allowed to expand adiabatically to a temperature by releasing the poston suddenly .If are the lengths of the gas column before and after expansion respectively, then is given bya.b.c.d.

33. Problem32Starting with same initial conditions, an ideal gas expands from volume in three different ways .The work done by the gas is if the process is purely isothermal, if purely isobaric and if purely adiabatic. Thena.b.c.d.

34. Problem33The plots of intensity versus wavelength for three black bodies at temperature respectively are as shown. their temperatures are such thata.b.c.d.

35. Problem34Two rasioctive materials have decay constants and respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of to that of will be 1/e after a timea.b.c.d.

36. Problem35In a double slit experiment, instead of taking slits of equal widths, one slit is made twice as wide as the other. Then ,in the interference patternthe intensities of both the maxima and the minima increase.the intensity of the maxima increases and the minima has zero intensity.the intensity of the maxima decreases and that of the minima increases.the intensity of the maxima decreases and the minima has zero intensity.

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