This document contains an unsolved physics exam from 1983 with 15 multiple choice questions and 5 fill-in-the-blank questions covering topics like mechanics, electromagnetism, optics, modern physics, and radioactivity. The questions test fundamental concepts and calculations involving kinematics, forces, electric and magnetic fields, waves, quantum mechanics, and radioactive decay.

1. IIT JEE –Past papers PHYSICS- UNSOLVED PAPER - 1983

2. SECTION – I Single Correct Answer Type Select the correct answer from among those provided for the following

3. 01 Problem A river is flowing from west to east at a speed of 5 meters per minute. A man on the south bank of the river, capable of swimming at 10 meters per minute in still water, wants to swim across the river in the shortest time. He should swim in a direction. Due north 300 east of north 300 west of north 600 east of north

4. Problem 02 If g is the acceleration due to gravity on the earth’s surface, the gain in the potential energy on object of mass m raised from the surface of the earth to a height equal to the radius R of the earth, is a. b.2mgR mgR d. mgR

5. Problem 03 A thin circular ring of mass M and radius r is rotating about its axis with a constant angular velocity Two objects, each of mass m, are attached gently to the opposite end of a diameter of the ring. The wheel now rotates with an angular velocity M/(M + m) ( M – 2m)/(M + 2m ) M/(M + 2m) (M + 2m)/M

6. Problem 04 A U-type of uniform cross section (see Fig.1) is partially filled with a liquid I. Another liquid II which does not mix with liquid I is poured into one side. It is found that the liquid levels of the two sides of the tube are the same, while the level of liquid I has risen by 2 cm. I f the specific gravity of liquid I is 1.1, the specific gravity of liquid II must be 1.12 1.1 1.05 1.0

7. Problem 05 An ideal mono-atomic gas is taken round the cycle ABCDA as shown in the p-V diagram (see Fig.2). The work done during the cycle is PV 2pV ½ p V Zero

8. Problem 06 A hollow metal sphere of radius 5 cm is charged such that the potential on its surface is 10 volts. The potential at the centre of the sphere is Zero 10V same as at a point 5 cm away from the surface same as at a point 25 cm away from the surface

9. Problem 07 The current i in the circuit (see Fig.3) is (1/45) A (1/15) A (1/10) A (1/5) A

10. Problem 08 A conducting circular loop of radius r carries a constant current i. It is placed in in a uniform magnetic field such that is perpendicular to the plane of the loop. The magnetic force acting on the loop is a. 2 Zero d.

11. Problem 09 A ray of light from a denser medium strikes a rarer medium at an angle of incidence i(see Fig.4.) The reflected and refracted rays make an angle of 900 with each other. The angles of reflection and refraction are r and r’. The critical angle is given by sin-1 (tan r) sin-1 (tan r’) sin-1 (tan i) sin-1 (sin i)

12. Problem 10 Beta rays emitted by a radioactive material are Electromagnetic radiations The electrons orbiting around the nucleus Charged particles emitted by the nucleus Neutral particles

13. Problem 11 If elements with principal quantum number n > 4 were not allowed in nature, the number of possible elements would be 60 32 4 64

14. Problem 12 Consider the spectral line resulting from the transition in the atoms and ions given below. The shortest wavelength is produced by Hydrogen atom Singly ionized helium Deuterium atom Doubly iodized lithium

15. Problem 13 The plate resistance of a triode value is 3 x 103 ohms and its mutual conductance is 1.5 x 10-3 amp/volt. The amplification factor of the triode is 5 x 10-5 4.5 0.45 2 x 106

16. Problem 14 The equation represents -decay -decay fusion fission

17. SECTION – II Match the following Match the physical quantities given in column I with dimensions expressed in terms of mass (M), length (L) time (T) and change (Q) given in column II and write the correct answer against the matched quantity in a tabular form in your answer book

18. Problem 01 I II Angular momentum ML2T-2 Latent heat ML2Q-2 Torque ML2T-1 Capacitance ML3T-1Q-2 Inductance M-1L-2T2Q2 Resistivity L2T-2

19. SECTION – III Fill in the blanks Read the following statements carefully. Indicate the subdivision number and write the matter corresponding to the blanks strictly in the order they appear in the statement.

20. Problem 01 A particle moves in a circle of radius R. In half the period of revolution, its displacements are _________ and the distance covered is ______________.

21. Problem 02 A traveling wave has the frequency v, and the particle displacement amplitude A. For the wave. The particle velocity amplitude is ___________ and the particle acceleration amplitude is _______________.

22. Problem 03 A light wave of frequency 5 x 1014 Hz enters a medium of refractive index 1.5. In the medium, the velocity of the light wave is _________ and its wave length is ______.

23. Problem 04 To produce characteristic X-rays using a Tungsten target in an X-ray generator, the accelerating voltage should be greater than _______________ volts and the energy of the characteristic radiation is _________ eV. (The binding

24. Problem 05 The radioactive decay rate of a radioactive element is found to bo 10 disintegrations/second at a certain time. If the half-life of the element is one second, the decay rate after one second is __________ and after three seconds is __________.

25. FOR SOLUTION VISIT WWW.VASISTA.NET