AFMC Physics -2009

AFMC–Past papers: 

AFMC–Past papers PHYSICS- UNSOLVED PAPER - 2009

SECTION – A: 

SECTION – A Single Correct Answer Type 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

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01 The speed of sound in air is 332 m/s 662 m/s 540 m/s 784 m/s Problem

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Problem 02 Which one is self adjusting force? Kinetic friction Static friction Nuclear force None of these

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Problem 03 If series combination of two inductors has a value 10 H and parallel combination 2.4 H, the difference between values of two inductors is 10 H 3 H 6 H 2 H

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Problem 04 Angle between magnetic meridian and geographical meridian is called angle of dip angle of declination angle of depression both (a) and (b)

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Problem 05 Rain drops are spherical due to surface tension viscosity gravity due to contraction

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Problem 06 At what temperature surface tension of water is minimum? 0°C 25°C 50°C 70°C

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Problem 07 What is incorrect about photon? Its rest mass is 0 Its energy is hv Its momentum is hv /c It does not exert pressure

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Problem 08 What is the rigidity modulus of liquid? 1 0 ∞ None of these

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Problem 09 Which one is used in ionosphere propagation? U.V rays IR rays Radio waves Light waves

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Problem 10 If both the charges and distance between them is doubled then new electrostatic force will be F 2F 0 none of these

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Problem 11 What are the dimensions of permeability? M 1 L 1 T 1 A -2 M1L1T -2 A -2 M 2 L 2 T 1 A 0 M 1 L 2 T 2 A -2

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Problem 12 What is not released in nuclear disintegration? Electrons Protons Helium nucleus y rays

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Problem 13 If a hollow cylindrical conductor having positive charge is placed near another neutral conductor. The net charge induced on neutral conductor is Positive negative depends on distance zero

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Problem 14 Weightlessness in satellite is due to zero gravitational acceleration zero acceleration zero mass none of these

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Problem 15 If two lenses of power +20 D and -40 D are combined, the resulting power is +20 D -20 D +40 D -40 D

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Problem 16 Two identical mercury drops, each of radius r are charged to the same potential V. If the mercury drops coalesce to form a big drop of radius R, then potential of the big drop will be (2) 3/2 V (3) 1/2 V (3) 2/3 V (2) 2/3 V

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Problem 17 P,V,T respectively denote pressure, volume and temperature of two gases. On mixing, new temperature and volume are respectively T, V. Final pressure of the mixture is P 2P zero 3F

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Problem 18 Which of the following elements is a semiconductor? Na Ba Sr Ge

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Problem 19 Which of the following law refers the direction of induced emf ? Biot - Savart's law Ampere's circutal law Kirchoff's law Lenz's law

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Problem 20 What would be the acceleration due to gravity at another planet whose mass and radius are twice of that of earth? 2g g g/4 B/2

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Problem 21 The current in the coil of inductance 10 H decreases from 10 amp to 5 amp in 0.2 sec, then the induced emf will be 50 V 500 V 250 V 100 V

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Problem 22 The value of acceleration due to gravity on moving from equator to poles will decrease increase remain same become half

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Problem 23 In n-p-n transistor circuit the collector current is 5 mA . -If 98% of electrons emitted reach the collector then the emitter current will be 8.1 mA 5.1 mA 10 mA 5 mA

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Problem 24 Diode can work as demodulator modulator amplifier rectifier

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Problem 25 Which of the following element has highest first ionization potential? As Bi Sb N

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Problem 26 The work function of a metallic substance is 5 eV . The threshold frequency is approximately 1.6 x 10 7 Hz 8.68 x 10 15 Hz 9.68 x 10 17 Hz 1.2 x 10 15 Hz

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Problem 27 A machine gun has a mass 5 kg. It fires 50 gram bullets at the rate of 30 bullets per minute at a speed of 400 m/s. Force required to keep the gun in position is 10 N 5 N 15 N 30 N

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Problem 28 A ball is thrown up with velocity 19.6 m/s. The maximum height attained by the ball is 29.2 m 9.8 m 19.6 m 15.8 m

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Problem 29 A train A which is 120 m long is running with velocity 20 m/s while train B which is 130 m long is running in opposite direction with velocity 30 m/s. What is the time taken by train B to cross the train A? 5 sec 25 sec 10 sec 100 sec

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Problem 30 The value of critical angle is least for which of the following colours of light? Violet Green Blue Yellow

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Problem 31 The excess pressure of X bubble is 4 times the excess pressure of bubble Y. Then the ratio of their volumes is 4 : 1 1 : 64 64 : 1 2 : 1

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Problem 32 If the mass of the body is halved and velocity gets doubled then final kinetic energy would be of initial same four times double eight times

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Problem 33 The energy of a string is U J when stretched by 2 cm. If the same string is stretched by 10 cm. The energy of string would be U J 50UJ 5 U J 25U J

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Problem 34 A train of weight 107 N is running on a level track with uniform speed of 36 km h_1. The frictional force is 0.5 kgf per quintal. If g = 10 m/s2, power of engine is 500 kW 50 kW 5 kW 0.5 kW

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Problem 35 A car is moving along a circular road at speed of 20 m/s. The radius of the circular road is 10 m. If the speed is increased at the rate of 30 m/s2, what is the resultant acceleration? 10 m/s 2 50 m/s 2 250 m/s 2 80 m/s 2

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Problem 36 If R is universal gas constant, the amount of heat needed to raise the temperature of 2 moles of an ideal monatomic gas from 273 K to 373 K when no work is done is 100R 150-R 300R 500R

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Problem 37 The ratio of thermal conductivity of two rods of different materials is 5 : 4. The two rods having same area of cross section and same thermal resistance have the lengths in the ratio 5 : 4 1 : 9 9 : 1 4 : 5

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Problem 38 A block is resting on a piston which is moving vertically with S.H.M. of period 1.0 s. At what amplitude of motion will the block and piston separate? 0.2 m 0.25 m 0.3 m 0.35 m

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Problem 39 The equation of a stationary wave along a stretched string is given by where x and y are in cm and t is in sec. The separation between two adjacent nodes is 3 cm 1.5 cm 6 cm 4 cm

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Problem 40 Every atom makes one free electron in copper. If 1.1 ampere current is flowing in the wire of copper having 1 mm diameter, then the drift velocity (approx) will be (density of copper = 9 x 10 3 kg m -3 and atomic weight of copper = 63) 0.1 mm/s 0.2 mm/s 0.3 mm/s 0.2 cm/s

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Problem 41 Five equal resistors when connected in series dissipated 5 watt power. If they are connected by parallel, the power dissipated will be 25 W 50 W 100 W 125 W

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Problem 42 A TV tower has a height of 100 m. How much population is covered by the TV broadcast if the average population density around the tower is 1000 km -2 ? (radius of the earth = 6.37 x l0 6 m) 4 lakh 4 billion 40,000 40 lakh

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Problem 43 Two sources of light of wavelengths 2500 A and 3500 A are used in Young's double slit experiment simultaneously. Which orders of fringes of two wavelength patterns coincide? 3 rd order of 1 st source and 5 th order of 2 nd 7 th order of 1 st and 5 th order of 2 nd 5 th order of 1 st and 3 rd order of 2 nd 5 th order of 1 st and 7 th order of 2 nd

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Problem 44 The magnet of pole strength m and magnetic moment M is cut into two pieces along its axis. Its pole strength and magnetic moment now become a. b. c. d. m,M

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Problem 45 A nichrome wire 1 m long and 1 mm2 in crosssection area draws 4 ampere at 2 volt. The resistivity of nichrome is 1 x 10 -7 Ω m 2 x 10 -7 Ω m 4 x 10 -7 Ω m 5 x 10 -7 Ω m

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Problem 46 A car travelling at a speed of 30 km h -1 is brought to a halt in 8 m by applying brakes. If the same car is travelling at 60 km h"1, it can be brought to a halt with the same braking power in 32 m 24 m 16 m 8 cm

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Problem 47 A solid cylinder of mass 20 kg rotates about its axis with angular speed 100 rad /s. The radius of the cylinder is 0.25 m. The K.E. associated with the rotation of the cylinder is 3025 J 3225 J 3250 J 3125 J

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Problem 48 A spring of force constant k is cut into two pieces whose lengths are in the ratio 1 : 2. What is the force constant of the longer piece? k/2 3k/2 2k 3k

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Problem 49 The reading of Centrigrade thermometer coincides with that of Fahrenheit thermometer in a liquid. The temperature of the liquid is - 40°C 313°C 0°C 100°C

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Problem 50 The magnetic lines of force inside a bar magnet are from north pole to south pole of the magnet do not exist depend upon the area of cross-section of the bar magnet are from south pole to north pole of the magnet.

Slide 53: 

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