AFMC Physics

PHYSICS SECTION (AFMC)Q1. The radius of curvature of a spherical surface is measured usingA. a spherometerB. spectrometer C. screw gaugeD. slide calipersQ2. If the dimensions of length are expressed as G x, C y, h z, where G, C, h is universal gravitational constant, speed of light and Plank's constant respectively, then A. x = 1/2, y = ½B. x = 1/2, z = 1/2 C. y = 1/2, z = 3/2D. y = + 3/2, z = ½Q3. The dimensional formula of electric field strength is: A. MLT-2 I-1B. MLT-3A-1 C. T-2A-1 D. MLTA-2Q4. A man throws a ball in air in such a way that when the ball is in its maximum height he throws another ball. If the balls are thrown after the time difference of 1 sec, then what will be the height attained by themA. 19.6 mB. 9.8 mC. 4.9 m D. 2.45 mQ5. If the velocity time graph of a body is a straight line sloping downwards, the body has A. accelerationB. declaration C. zero accelerationD. constant accelerationQ6. Which one of the following equations represents the motion of body with finite constant acceleration? A. y = atB. y = at + bt2 C. y = at + bt 2 + ct3D. y = at + btQ7. What is the magnitude of the velocity of the body when it is projected horizontally from a point above the ground after 0.2 seconds?A. 2 ms-1B. 22 ms-1C. 32 ms-1D. 42 ms-1 Q8. A string can withstand a tension of 25 N. What is the greatest speed at which a body of mass 1 kg can be whirled in a horizontal circle using 1 m length of the string?A. 25 ms-1 B. 5 ms-1 C. 75 ms-1D. 10 ms-19. An object tied to a piece of string is whirled in a vertical circle, at constant speed. The tention in the string is maximum atA. AB. BC. CD. D10. The maximum force of friction that comes into play is calledA. limiting frictionB. kinetic frictionC. static frictionD. minimum friction11. A body of mass 5 Kg is raised vertically to a height of 10 m by a force of 170 N. The final velocity of the body isA. 15 ms-1 B. 17 ms-1C. 20 ms-1 D. 22 ms-112. A cyclist moving at a speed of 17.64 km/h describes a circle of radius 9.8 m. If the cyclist is held in balance, the co-efficient of friction between the tyre and the ground isA. 0.25B. 0.29C. 0.36D. 0.35 13. Two bodies with masses m1 and m2 have equal kinectic energies. If P1 and P2 are their respective momenta, then P1 = P2 isA. m1 : m2B. m2 : m1C. m12 : m22D. m1 : m214. In elastic collision,A. only energy is conservedB. only momentum is conservedC. both energy and momentum is conservedD. none of these15. The velocity of a particle whose kinetic energy is equal to the rest energy isA. (1/2) C B. C C. 3/3D. 3 C16. The propeller of a ship makes 350 rev. while its speed increases from 200 rpm to 500 rpm. Then the time taken for this isA. 1 minB. 1.2 minuteC. 5.3 seconds D. 53 seconds17. The K.E. needed to project a body from the earth's surface to infinity isA. mgRB. 2 mgR C. 1/2 (mgR)D. 1/4 (mgR)18. The distance of two planets from the sun are 1013 and 1012 meters respectively. The ratio of time period of these two planets is A. 10B. 1/10C. 100 D. 101019. Poisson ratio is the ratio ofA. the linear strain to the lateral strainB. the lateral strain to the linear strainC. the linear stress to the lateral stressD. the lateral stress to the linear stress20. Two wires L and M are of the same material and of the same length, but the diameter of L is twice that of M stretching force applied to L is four times that of M. Then the ratio of the elongation of L to that of M is A. 1 : 4B. 4 : 1C. 1 : 1D. 2 : 121. Which of the substance breaks just beyond the elastic limit?A. ElasticB. MalleableC. BrittleD. Ductile 22. A stone of mass 16 kg is attached to a string 144-meter-long and is whirled in a horizontal circle. The maximum tension the string can stand is 16 N. The maximum velocity of revolution that can be given to the stone without breaking it will beA. 12 ms-1B. 14 ms-1 C. 16 ms-1 D. 20 ms-1 23. A vessel containing 0.1 m3 of air at 76 cm of Hg pressure is connected to an evacuated vessel of capacity 0.09 m3. The resultant air pressure isA. 20 cm of HgB. 30 cm of HgC. 40 cm of HgD. 50 cm of Hg 24. Two gases A and B having the same temperature T, same pressure P and the same volume V are mixed. If the mixture is at the same temperature T and occupies a volume V, the pressure of the mixture isA. PB. 2PC. P/2D. 4P 25. A solid ball of metal has spherical cavity inside it. If the ball is heated, the volume of the cavity willA. increaseB. decrease C. remain the same D. disappear 26. If the law of heat conduction is written in the form of Ohm's law, then the quantity similar to electrical resistance is A. A/dB. Ad/C. A/dD. d/A27. The work done from 250 cals of heat isA. 1045 ergsB. 1045 joulesC. 1045 wattD. 1045 N28. The time taken by a particle executing S.H.M of period T to move the mean position to half the maximum displacement isA. T/2B. T/4C. T/8D. T/1229. Let g be the acceleration due to gravity at earth's surface and K be the rotational K.E. of the earth. Suppose the earth's radius decreases by 2%, thenA. g decreases by 2% and K decreases by 4%B. g decreases by 4% and K increases by 2%C. g increases by 4% and K decreases by 4%D. g decreases by 4% and K increases by 4%30. A particle of mass m is hanging vertically by an ideal spring of force constant K. If the mass is made to oscillate vertically, its total energy isA. maximum at the extreme positionB. maximum at the equilibrium C. minimum at the equilibrium D. same at all position31. Velocity of sound in CO2 is less than in hydrogen becauseA. CO2 is heavier than hydrogenB. CO2 is a compound and hydrogen is an element C. CO2 is more soluble in water D. CO2 can be more easily liquefied32. The velocity of sound in air at room temperature is 110 m/sec. The length of the wave coming from a vibrating fork at frequency 275 isA. 0.4 m B. 100 m C. 825 m D. 1375 m33. The temperature at which velocity of sound in air is double its velocity at 0°C isA. 435°CB. 694°CC. 781°CD. 819°C 34. Static electricity is produced byA. inductionB. frictionC. both induction and frictionD. none of the above35. Surface charge density on a pear shaped conductor isA. maximum in the middle positionB. maximum near the tapering endC. maximum near the broad endD. equal throughout the surface36. A given charge situated at a certain distance from an electric dipole in the end on position experiences a force F. If the distance of the charge is doubled, the force acting on the charge will beA. 2FB. F/2C. F/4D. F/837. A piece of fuse wire melts when the current is 5 A. The energy produced then is 1 J/s. The resistance of the fuse in ohm isA. 0.04B. 0.1C. 0.5D. 1038. The gravitational force between two point masses m1 and m2 at separation r is given byF = (m1m2)/r2 Then constant KA. depends on systems of units only B. depends on medium between masses only C. depends of both masses and unitsD. none of these 39. A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance ofA. each of them increases B. each of them decreases C. copper increases and germanium decreases D. germanium increases and copper decreases40. In a given thermocouple, the temperature of the cold junction is 20°C, while the neutral temperature is 27°C. What will be the temperature of immersion?A. 420°CB. 425°CC. 520°CD. 525°C 41 When different parts of a metal are kept at different temperature and current is passed through it, heat is either evolved or absorbed. The effect is called A. Peltier effect B. Seebeck effect C. Thompson effectD. Joule effect42. A storage battery is to be charged from a d.c. supply which terminal of the battery be connected to the positive side of the lineA. positiveB. negativeC. both positive and negativeD. first negative and after the lapse of 5 minutes positive43. The force between two parallel wires carrying currents in the same direction is aA. force of attractionB. force of repulsionC. no resultant force between the wiresD. resultant force acting perpendicular to the flow of wires44. The motion of an electric charge producesA. only an electric fieldB. only a magnetic field C. both magnetic and electric field D. none of the above45. An ammeter is connected in series with a 2V circuit containing a 2V battery when the switch is closed, the ammeter shows high deflection and comes to zero. The circuit may contain aA. resistance of 20 B. fuse C. diode D. triode 46. Ferromagnetic substances have A. very high permeability and susceptibility B. low permeability but high susceptibility C. high permeability and low susceptibility D. none of these47. The permeability of the paramagnetic substance isA. very largeB. very smallC. negativeD. small but more than 148. When a material is subjected to a small field H, the intensity of magnetization is proportional toA. HB. HC. H2D. 1/H 49. In a capacitance circuit the resistance is A.  C B. 1/ CC. 1/ C D  x C50. In electromagnetic induction, the induced e.m.f. is independent ofA. change of flux B. time C. number of lines of force D. resistance of the cells