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AFMC–Past papers<br />PHYSICS- UNSOLVED PAPER - 1995<br />
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SECTION – A<br />Single Correct Answer Type<br />There are five parts in this question. Four choices are given for each part and one of them is correct. Indicate you choice of the correct answer for each part in your answer-book by writing the letter (a), (b), (c) or (d) whichever is appropriate<br />
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Problem<br />01<br />In figure the potentiometer wire AB has a resistance of 5Ω and length 10 m the balancing length AJ for the e.m.f of 0.4 V is<br />0.8m<br />4m<br />0.4m<br />1.5m<br />
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Problem<br />02<br />The primary winding of a transformer has 500 turns whereas its secondary has 5000 turns. The primary is connected to an AC supply 20 V, 50 Hz. The Secondary will have an output of<br />2 v , 50 Hz<br />200V, 50 Hz<br />2V, 5Hz<br />200V, 500Hz<br />
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Problem<br />03<br />The blue color of the sky is due to the phenomenon of<br />Scattering <br />Reflection<br />Dispersion<br />Refraction<br />
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Problem<br />04<br />The capacity of a parallel plate capacitor increases with the<br />Increase of its area<br />Decrease of its area<br />Increase of its distance<br />None of these<br />
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Problem<br />05<br />A student has 10 resistors of resistance r. The minimum resistance made by him from the give resistors is<br />r/100<br />10r<br />r/5<br />r/10<br />
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Problem<br />06<br />Which one of the following gates correspond to the truth table given below<br />NAND<br />XOR<br />NOR<br />OR<br />
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Problem<br />07<br />Which of the following quantity is expressed as force per unit area?<br />Volume<br />Work<br />Area<br />Pressure<br />
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Problem<br />08<br />The displacement-time graph of a moving particle is shown below. The instantaneous velocity of the particle is negative as the point<br />E<br />F<br />C<br />D<br />
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Problem<br />09<br />The equation constant. The unit of a is<br />Dyne/cm3<br />Dyne/cm5<br />Dyne x cm2<br />Dyne x cm4<br />
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Problem<br />10<br />Water falls from a height of 800 m. if whole of its energy changes to heat, what would be the rise in its temperature when it reaches the ground (1 kcal=4200J)<br />1.860c<br />1.180c<br />00c<br />0.530c<br />
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Problem<br />11<br />The twinkling of stars is due to the<br />Refractive index of the earth’s atmosphere fluctuates<br />Fact that stars do not emit light continuously <br />Both (a) and (b)<br />None of these<br />
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Problem<br />12<br />At sun rise or sunset, the sun looks more red than at mid-day, because of the<br />Effects of refraction<br />Sun is hottest at these times<br />Effects of diffraction<br />Scattering of light<br />
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Problem<br />13<br />The volume of atoms to the volume of nit cell is called<br />Coordination number <br />Packing fraction<br />Lattice parameter<br />Packing coefficient<br />
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Problem<br />14<br />a body moves due east with velocity 20km/hour and then due north with velocity 15 km/hour. The resultant velocity<br />20 km/hour<br />5 km/hour<br />25 km/hour<br />15 km/hour<br />
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Problem<br />15<br />A dip circle is at right angle to the magnetic meridian. What will be its apparent dip?<br />600<br /> 00<br />900<br />300<br />
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Problem<br />16<br />Six resistors of 3Ω each are connected along the sides of a hexagon and three resistors of 6Ω each are connected along AC, AD and AE as shown in the figure. The equivalent resistance between A and B is equal to <br />2 Ω<br />3 Ω<br />6 Ω<br />9 Ω<br />
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Problem<br />17<br />The direction of magnetic field line of bar magnet is<br />Across the bar magnet <br />From south pole to north pole<br />From south pole to north pole inside the magnet and from north pole to south pole outside the magnet<br />From north pole to south pole<br />
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Problem<br />18<br />When Ge crystals are doped with phosphorus atom, then it becomes<br />n-type semiconductor<br />insulator <br />superconductor<br />p-type semiconductor<br />
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Problem<br />19<br />In which radioactive disintegration, neutron dissociates into proton and electron?<br />λ- emission<br />He++ emission <br />Positron emission<br />Β-emission<br />
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Problem<br />20<br />The focal length of convex lens is 30cm and the distance of image is quarter of the object, then the object distance is<br />40cm <br />90cm<br />30cm<br />60cm<br />
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Problem<br />21<br />When the number of turns and length of a solenoid are doubled, keeping the area of cross-section same, the inductance<br />Is doubled<br />Is halved<br />Becomes four times<br />Remains the same<br />
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Problem<br />22<br />A solenoid is at potential difference of 60V. if the current flowing through it is 15 ampere, then resistance of the coil will be<br />0.25 Ω<br />4 Ω<br />2 Ω<br />8 Ω<br />
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Problem<br />23<br />Bending of light about the corner of an obstacle sharp edged is called<br />Polarization<br />Deviation<br />Diffraction<br />Dispersion<br />
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Problem<br />24<br />If a source of light is moving away from a stationary observer, then frequency of light wave appears to change because of<br />Diffraction<br />Doppler’s effect<br />Refraction<br />Interference<br />
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Problem<br />26<br />In the case of forward biasing of p-n junction, which one of the following figures correctly depicts the direction of flow of carriers?<br />a.<br />b.<br />c.<br />d.<br />
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Problem<br />27<br />A galvanometer is converted into ammeter, when we connect<br />Low resistance in series <br />High resistance in series <br />Low resistance in parallel<br />High resistance in parallel<br />
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Problem<br />28<br />In an experiment with Kund’s tube the distance between consecutive nodes is 5 cm when air is inside, and it is 13.4 cm when hydrogen is inside calculate the velocity of sound in hydrogen(speed of sound in air = 330m/s)<br />424m/s<br />884.4 m/s<br />1024.8 m/s<br />864.4 m/s<br />
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Problem<br />29<br />The splitting of line into groups under the effect of electric or magnetic field is called<br />Heisenberg's effect<br />Bohr’s effect<br />Magnetic effect <br />Zeeman’s effect<br />
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Problem<br />30<br />Two open organ pipes of length 25 cm and 25.5 cm produce 0.1 beats/sec. the velocity of sound is<br />303 m/s<br />350 m/s<br />255 m/s<br />325.5 m/s<br />
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Problem<br />31<br />On the absolute scale of temperature given by Kelvin, steam point has a value of<br />-273 K<br />373 K<br />0 K<br />273 K<br />
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Problem<br />32<br />If the radius of curvature of convex mirror is 40 cm and distance of image is twice as that of object, then the object distance is<br />30 cm<br />60 cm<br />20 cm<br />40 cm<br />
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Problem<br />33<br />The minimum energy required to remove an electron is called<br />Stopping potential <br />Work function<br />Potential energy <br />Kinetic energy<br />
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Problem<br />34<br />Two waves of the same frequency and intensity superimpose with each other in opposite phases after the superposition, the<br />Frequency increases by 4 times<br />Intensity increases by 4 times<br />Intensity increases by two times<br />None of these <br />
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Problem<br />35<br />The sensitivity of a tangent galvanometer is increased, if<br />Field is increased <br />Number of turns decreased<br />Field is decreased<br />Number of turns increased<br />
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Problem<br />36<br />The resistance of a wire is R. If the length of the wire is doubled, then its resistance will be<br />R<br />2R<br />0.25 R<br />4 R<br />
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Problem<br />37<br />Which of the following has a negative temperature coefficient?<br />Man<br />C<br />Ag<br />Fe<br />
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Problem<br />38<br />Radiation emitted by a surface is directly proportional to<br />Twice power of its temperature<br />Third power of its temperature<br />Equal to its temperature<br />Fourth power of its temperature<br />
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Problem<br />39<br />A rectangle ABCD is such that BC = 2 AB. The moment of inertia along axis will be minimum through<br />HF<br />BC<br />EG<br />BD<br />
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Problem<br />40<br />In an isothermal expansion, the pressure is determined by<br />Compressibility only <br />Temperature only<br />Both (a) and (b)<br />None of these<br />
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Problem<br />41<br />Monochromatic light wave means <br />A beam of white colour<br />A beam of the same colour<br />A cluster of beam of different colours<br />None of these<br />
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Problem<br />42<br />Time period of a simple pendulum will be double, if we<br />Decrease the length 4 times<br />Increase the length 4 times<br />Decrease the length 2 times<br />Increase the length 2 times<br />
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Problem<br />43<br />Soap bubble appears coloured due to the phenomenon of<br />Dispersion <br />Interference<br />Reflection<br />Diffraction<br />
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Problem<br />44<br />The translational kinetic energy of gas, for one mole of the gas, is equal to<br />a.<br />b.<br />c.<br />d. <br />
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Problem<br />45<br />If we move from equator to pole, the value of g<br />Remains the same <br />Increases <br />Decreases <br />First (b) then (c)<br />
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Problem<br />46<br />If the critical temperature of CO2 is 31.10C and room temperature is 400C, then CO2 behaves as<br />Liquid <br />Gas<br />Gas and vapour<br />Vapour<br />
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Problem<br />47<br />The minimum wavelength of the X-rays produced by electrons accelerated through a potential difference of V volts is directly proportional to<br />1/√V<br />√V <br />1/V<br />V2<br />
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Problem<br />48<br />A bullet of mass 0.1 kg is fired with a speed of 100m/sec, the mass of gun is 50 kg. The velocity of recoil is<br />0.5 m/sec<br />0.2 m/sec<br />0.05 m/sec<br />0.1 m/sec<br />
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Problem<br />49<br />A hollow metallic sphere of radius 10 cm is charged such that potential of its surface is 70 volts. The potential at the centre of the sphere would be<br />70V<br />0V<br />700V<br />7V<br />
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Problem<br />50<br />A ball is thrown upwards with a velocity of 100m/sec. it will reach the ground after<br />10 sec<br />40 sec<br />5 sec<br />20 sec<br />
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