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aipmt–Past papers<br />PHYSICS- UNSOLVED PAPER - 1995<br />
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SECTION – I (Total Marks : 50)<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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01<br />Problem<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 />02<br />Distance between body centered atom and a corner atom in sodium (a = 4.225 Å) is <br />2.99 Å<br />2.54 Å<br />3.66 Å<br />3.17 Å<br />
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Problem<br />03<br />What is the respective number of and - particles emitted in the following radioactive decay?<br />8 and 8<br />8 and 6<br />6 and 8<br />6 and 6.<br />
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Problem<br />04<br />The binding energies per nucleon for a deuteron and an -particle are x1 and x2 respectively. The energy Q released in the reaction 2H1+2H1 4He2 + Q, is <br />4(x1 + x2)<br />4(x1 - x2)<br />2(x2 – x1)<br />2(x1 + x2)<br />
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Problem<br />05<br />The count rate of a Geiger Muller counter for the radiation of the a radioactive material of half-life of 30 minutes decreases to 5 second-1 after 2 hours. The initial count rate wave <br />80 second –1<br />625 second-1<br />20 second-1<br />25 second-1.<br />
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Problem<br />06<br />An electron makes a transition from orbit n = 4 to the orbit n = 2 of a hydrogen atom. What is the wavelength of the emitted radiations ? (R = Rydberg’s constant )<br />a.<br />b.<br />c.<br />d.<br />
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Problem<br />07<br />When a hydrogen atom is raised from the ground state to an excited state,<br />Both K.E. and P.E. increase <br />Both K.K. and P.K. decrease<br />The P.E. decrease and K.E. increases <br />The P.E. increase and K. E. decrease <br />
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Problem<br />08<br />In good conductors of electricity, the type of bonding that exists is <br />Metallic <br />Vander Waals<br />Ionic<br />Covalent.<br />
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Problem<br />09<br />The figure represents the observed intensity of X-rays emitted by an X-ray tube, as a function of wavelength. The sharp peaks A and B denote A and B denote <br />What radiations <br />Characteristic radiations <br />Band spectrum <br />Continuous spectrum <br />
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Problem<br />10<br />An electron of mass m, when accelerated through a potential difference, V, has de Broglie wavelength The de Broglie wavelength associated with a proton of mass M accelerated through the same potential difference, will be<br />a.<br />b.<br />c.<br />d.<br />
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Problem<br />11<br />A charge q is placed at the center of the line joining two exactly equal positive charges Q. The system of three charges will be in equilibrium, if q is equal to<br />-Q<br />Q/2<br />-Q/4<br />+Q.<br />
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Problem<br />12<br />If we consider electrons and photons of same wavelength, then they will have same <br />Momentum <br />Angular momentum <br />Energy <br />Velocity.<br />
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Problem<br />13<br />There is electric field E in x-direction. If the work done on moving a charge of 0.2 C through a distance of 2 m along a line making an angle 600 with x-axis is 4 J, then what is the value of E? <br />5 N/C<br />20 N/C<br /> N/C<br />4 N/C.<br />
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Problem<br />14<br />Two metallic spheres of radii 1 cm and 2 cm are given charges 10-2 C and 5 x 10-2C respectively If they are connected by a conducting wire, the final charge on the smaller sphere is <br />3 x 10-2 C<br />4 x 10-2 C<br />1 x 10-2 C<br />2 x 10-2 C<br />
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Problem<br />15<br />In the network shown in the figure, each of the resistance is equal to 2 . The resistance between the points A and B is <br />3 <br />4 <br />1 <br />2 <br />
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Problem<br />16<br />Two wires of the same metal have same length, but their cross-sections are in the ratio 3 : 1. They are joined in series. The resistance of thicker wire is 10 . The total resistance of the combination will be <br />40 <br />100 <br />5/2 <br />40 /3 .<br />
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Problem<br />17<br />A heating coil is labeled 100 W. 220 V. the coil is cut in half and the two pieces are joined in parallel. To the same source. The energy now liberated per second is <br />200 J<br />400 J<br />25 J<br />50 J.<br />
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Problem<br />18<br />For measuring temperatures in the range of 2000 to 25000C, we should employ <br />Gas thermometer<br />Platinum-rhodium thermometer<br />Barometer<br />Pyrometer.<br />
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Problem<br />19<br />A straight line conductor of length 0.4 m is moved with a speed of 7 m/s perpendicular to a magnetic filed of intensity 0.9 Wb/m2. the induced e.m.f. across the conductor is <br />5.04 V<br />25.2 V<br />1.26 V<br />2.52 V.<br />
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Problem<br />20<br />The work done in turning a magnet of magnetic moment M by an angle of 900 from the meridian, is n times the corresponding work done to turn it through an angle of 600. The value of n is given by <br />1/2<br />1/4<br />2<br />1.<br />
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Problem<br />21<br />When the key K is pressed at time t = 0, then which of the following statement about the current I in the resistor AB of the given circuit is true ?<br />I oscillates between 1 mA and 2 mA<br />At t = 0, I = 2 mA and with time it goes to 1 mA<br />I = 1 mA at all t <br />I = 2 mA at all t.<br />
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Problem<br />22<br />Exposure time of camera lens at f/2.8 setting is 1.200 second. The correct time of exposure at f/5.6 is <br />0.20. second<br />0.40 second<br />0.02 second<br />0.04 second.<br />
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Problem<br />23<br />The dimension of RC is <br />Square of time<br />Square of inverse time<br />Time <br />Inverse times<br />
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Problem<br />24<br />The figure indicates the energy level diagram of an tom and the origin of six spectral lines in emission (e.g. line no. 5 arises from the transition from level B to A). which of the following spectral lines will also occur in the absorption spectrum?<br />4,5,6<br />1,2, 3, 4, 5, 6<br />1, 2, 3<br />1, 4, 6.<br />
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Problem<br />25<br />A star, which is emitting radiation at a wavelength of 5000 Å, is approaching the earth with a velocity of 1.5 x 104 m/s. The change in wavelength of the radiation as received on the earth is <br />25 Å<br />100 Å<br />zero <br />2.5 Å<br />
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Problem<br />26<br />A lens is placed between a source of light and a wall. It forms images of area A1 and A2 on the wall, for its two different positions. The area of the source of light is <br /> <br />a.<br />b.<br />c.<br /> d.<br />
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Problem<br />27<br />In an A.C. circuit, the current flowing is amperes and the potential difference is V = 200 sin (100t) volts. The power <br />20 W<br />0 W<br />1000 W<br />40 W.<br />
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Problem<br />28<br />An ideal Carnot engine, whose efficiency is 40%, receives heat at 500 K. If its efficiency is 50% then the intake temperature for the same exhaust temperature is <br /> <br />800 K<br />900 K<br />600 K<br />700 K<br />
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Problem<br />29<br />Heat is flowing through two cylindrical rods of the same material. The diameters of the rods are in the ratio 1 : 2 and the lengths in the ratio 2 : 1. If the temperature difference between the ends is same, then ratio of the rate of flow of heat through them will be <br />2 : 1<br />8 : 1<br />1 : 1<br />1 : 8<br />
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Problem<br />30<br />Percentage errors in the measurement of mass and speed are 2% and 3 % respectively. The error in the estimate of kinetic energy obtained by measuring mass and speed will be <br />8%<br />2%<br />12 %<br />10%<br />
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Problem<br />31<br />An oscillator is nothing but an amplifier with <br />positive feed back <br />negative feed back <br />voltage gain<br />no feed back.<br />
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Problem<br />32<br />A source of sound gives 5 beats per second, when sounded with another source of frequency 100 second-1. The second harmonic of the source, together with a source of frequency 205 sec-1 gives 5 beats per second. What is the frequency of the source?<br />105 Second-1<br />205 Second -1<br />95 Second-1<br />100 Second-1<br />
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Problem<br />33<br />A hospital uses ultrasonic scanner to locate tumors in a tissue. The operating frequency of the scanner is 4.2 MHz The speed of sound in a tissue is 1.7 km/s. The wavelength of sound in the tissue is close to <br />4 x 10-3 m<br />8 x 10-3 m<br />4 x 10-4 m<br />8 x 10-4 m<br />
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Problem<br />34<br />In a simple harmonic motion, when the displacement is one-half the amplitude, what fraction of the total energy is kinetic? <br />1/2<br />3/4<br />zero<br />1/4<br />
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Problem<br />35<br />A beaker full of hot water is kept in a room. If it cools from 800C to 750C in t1 minutes, from 750C to 700C in t2 minutes and from 700C to 650C in t3 minutes, then <br />t1 < t2 < t3<br />t1 > t2 > t3<br />t1 = t2 = t3<br />t1 < t2 = t3.<br />
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Problem<br />36<br />The length of a son meter wire AB is 100 cm. Where should the two bridges be placed from A to divide the wire in 3 segments whose fundamental frequencies are in the ratio of 1 : 2 : 3?<br /> <br />60 cm and 90 cm<br />30 cm and 60 cm<br />30 cm and 90 cm<br />40 cm and 80 cm.<br />
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Problem<br />37<br />The earth (mass = 6 x 1024 kg) revolves around the sun with an angular velocity of 2 x 10-7rad/s in a circular orbit of radius 1.5 x 108 km. The force exerted by the sun on the earth, in Newton, is <br />36 x 1021<br />27 x1039<br />zero<br />18 x 1025.<br />
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Problem<br />38<br />Two particles of equal mass go around a circle of radius R under the action of their mutual gravitational attraction The speed v of each particle is<br />a.<br />b.<br />c.<br />d.<br />
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Problem<br />39<br />the mass number or He is 4 and that of sulphur is 32. The radius of sulphur nucleus is large than that of helium by the factor of <br />4<br />2<br />8<br />d.<br />
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Problem<br />40<br />The ABC is a triangular plate of uniform thickness. The sides are in the ratio shown in figure. I.AB IBC and ICA are the moments of inertia of the plate about AB, BC and CA respectively. Which one of the following relations is correct?<br />IAB + IBC = ICA<br />ICA is maximum <br />IAB > IBC<br />IBC > IAB.<br />
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Problem<br />41<br />The water drop falls at regular intervals from a tap 5 m above ground. The third drop is leaving the tap at instant the first drop touches the ground. How far above the ground is the second drop is that instant? <br />3.75 m<br />4.00 m<br />1.25 m<br />2.50 m.<br />
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Problem<br />42<br />A simple pendulum with a bob of mass m oscillates from A to C and back to A such that PB is H. If the acceleration due to gravity is g, then the velocity of the bob as it passes through B is <br />a. MgH<br />b. <br />c. zero <br />d. 2gH.<br />
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Problem<br />43<br />If the cold junction of a thermo- couple is kept at & the hot junction is kept at , then the relation between neutral temperature & temperature of inversion is<br />a.<br />b.<br />c.<br />d.<br />
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Problem<br />44<br />Assuming the sun to have a spherical outer surface of radius r, radiating like a black body at temperature , the power received by a unit surface ,( normal to the incident ray) at a distance R from the center of the sun is, ( is Stefan's constant) <br />a.<br />b.<br />c.<br />d.<br />
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Problem<br />45<br />In the energy band diagram of a material shown below, the open circles & filled circles denote holes & electron respectively. The material is<br />An insulator<br />A metal<br />An n-type semiconductor<br />An p-type semiconductor<br />
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Problem<br />46<br />The potential energy between two atoms, in a molecule, is given by <br /> where a and b are positive constants and x is the <br /> distance between the atoms. The atom is in stable equilibrium, when<br />a.<br />b.<br />c.<br />d. <br />
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Problem<br />47<br />the position vector of a particle is The velocity of the particle is <br />directed towards the origin<br />directed away from the origin <br />parallel to the position vector <br />perpendicular to the position vector. <br />
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Problem<br />48<br />What is the torque of the force acting at the point m about origin?<br /> a.<br />b.<br />c.<br />d.<br /> <br />
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Problem<br />49<br />Which of the following is a dimensional constant? <br />Relative density <br />Gravitational constant<br />Refractive index <br />Passions ratio.<br />
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Problem<br />50<br />The angular speed of a fly-wheel making 120 revolutions/minute is<br />4 rad/s<br />4 2 rad/s<br />rad/s<br />2 rad/s.<br />
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