This document contains an unsolved physics exam from 1982 with 10 multiple choice questions in Section I and 5 true/false statements in Section II related to physics concepts like kinematics, mechanics, optics, waves, electromagnetism, and thermodynamics. The questions assess understanding of fundamental physics principles including displacement under uniform motion, average acceleration, upthrust force, speed of particles moving toward each other, interference patterns in Young's double slit experiment, lens combinations, wave equations, magnetic fields, x-ray emission, and photoelectric effect thresholds.

1. IIT JEE –Past papersPHYSICS- UNSOLVED PAPER - 1982

2. SECTION – ISingle Correct Answer TypeThis section contains 10 multiple choice questions. Each question has four choices (A), (B), (C) and (D) out of which ONLY ONE is correct.

3. 01ProblemIn the arrangement as shown in the figure below, the ends P and Q of an inextensible string move downwards with uniform speed u. Pulleys A and B are fixed. Mass M moves upwards with a speed. a. 2u cos θb. u/cos θc. 2u/cos θd. ucos θ

4. Problem02A particle is moving eastwards with a velocity 5 m/s. In 10 seconds the velocity changes to 5 m/s northwards. The average acceleration in this time is a. Zero b. towards north-west c. towards north –west d. towards north

5. Problem03A body floats in a liquid contained in a beaker. The whole system as shown in the figure falls freely under gravity. The up thrust on the body due to the liquid is heard by the car driver isa. Zerob. Equal to the weight of the liquid displacedc. Equal to the weight of the body in aird. Equal to the weight of the immersed portion of the body

6. Problem04Two particles initially at rest move toward each other under a mutual force of attraction. At the instant when the speed of A is V and the speed of B is 2 V, then the speed at the centre of the mass of the system is a. Zerob. 1.5 Vc. V d. 3 V

7. Problem05In Young’s double slit experiment the interference pattern is found to have an intensity ratio between bright and dark fringes as 9. This implies that a. The intensities at the screen due to the two slits are 5 units and 4 units respectively. b. The intensities at the screen due to the slits are 4 units and 1 unit respectively.c. The amplitude ratio is three.d. The amplitude ratio is two.

8. Problem06A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of the combination is a. -1 .5 Db. -0.5 Dc. 6 .5 Dd. 6. 67 D

9. Problem07A wave equation which gives the displacement along y direction is given bywhere x and y are in meters and t is time in seconds. This represents a wavea. Traveling with a velocity of 30m/s in the negative x directionb. Of wave length meters.c. Of frequency 30/ Hertz.d. Of amplitude 10-4 m traveling along the negative x direction

10. Problem08A magnetic needle is kept in a non-uniform magnetic field. It experiencesa. A force and a torqueb. A force but not a torque.c. A torque but not a forced. Neither a force nor a torque

11. Problem09The shortest wavelength of x-rays emitted from an X-ray tube depends ona. The current in the tubeb. The voltage applied to the tube.c. The nature of the gas in the tubed. The atomic number of the target material

12. Problem10The threshold wavelength for photoelectric emission from a material is 5200Å Photoelectrons will be emitted when this material is illuminated with monochromatic radiation from a a. 50 watt red lampb. 1 watt neon lampc. 50 watt infrared lampd. 1 watt ultraviolet lamp

13. SECTION – IIEach of which either True or False This question contains five statements, each of which is either true of false. Indicate your choice of the answer in the answer-book by writing TRUE or FALSE for each statement.

14. Problem 11State whether the questions are true or falsei. The volume V versus temperature T graphs for a certain amount of a perfect gas at two pressures are as shown in the figure. It follows from the graph thatii. Two different gases at the same temperatures have equal root mean square velocities. iii. Electrons in a conductor have no motion in absence of a potential difference across it.

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