1) Holes can exist in____________________? a. Conductors b. Insulators c. Semi conductors d. All of the above
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2) In a semiconductors the charge carriers are ___________________? a. Holes only b. Electrons only c. Electron and holes both d. All of the above
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3) The net charge on n-type material is____________________? a. Positive b. Negative c. Both positive and negative d. Neutral
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4) Magnetic force acting on a unit positive charge moving perpendicular to the magnetic field with a unit velocity is called____________________? a. magnetic flux b. magnetic field intensity c. magnetic induction d. self inductance
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5) What is the value of the current in a wire of 10cm long at the right angle to a uniform magnetic field of 0.5 Weber/m2 when the force acting on the wire is 5N ? a. 1A b. 10A c. 100A d. 1000A
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6) Two parallel wires carrying currents in the opposite directions____________________? a. repel each other b. attract each other c. have no effect upon each other d. they cancel out their individual magnetic fields
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7) A magnetic field___________________? a. always exerts a force on a charged particle b. never exerts a force on a charged particles c. exerts a force if the charged particle is moving in the direction of the magnetic field lines d. exerts a force if the charged particle is moving perpendicular to the magnetic field lines
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8) Which one of the following material is most suitable for making core of an electromagnet ? a. air b. steel c. Cu-Ni alloy d. soft iron
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9) The relationship between Tesla and smaller unit Gauss of magnetic induction is given by_________________? a. 1T = 103 G b. 1T = 10-4 G c. 1T = 10-2 G d. 1T = 104 G
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10) SI unit of flux density is____________________? a. NA-1m-1 b. NAm-1 c. NmA-1 d. NmA-2
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11) The standard vector symbol for flux density is ____________________? a. M b. L c. H d. B
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12) An electron enters a region where the electric field E is perpendicular to the magnetic field B. It will suffer no deflection if_________________? a. E = BeV b. B = eE/V c. E = BV d. E = BeV/2
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13) An instrument which can measure potential without drawing any current is_____________________? a. voltmeter b. galvanometer c. cathode ray oscilloscope (CRO) d. ammeter
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14) When the coil of the galvanometer is in equilibrium then the deflecting couple is____________________? a. zero b. equal to the restoring couple c. greater than the restoring couple d. smaller than the restoring couple
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15) Which one of the following is not an electromechanical instrument ? a. galvanometer b. voltmeter c. ammeter d. AC transformer and DC generator
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16) In a multi range ammeter as the range increases _____________________? a. shunt value decreases b. shunt value increases c. shunt value remains the same d. none of the above
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17) A sensitive galvanometer gives full-scale deflection with 100 mV. If the resistance of the galvanometer is 50? the maximum current that can flow through safely is__________________? a. 2.0 mA b. 20 mA c. 200 mA d. 0.2 mA
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18) Coil of a galvanometer is suspended in a radial magnetic field so that the deflecting torque on the coil is always___________________? a. BINA cosa b. BINA sina c. BINA tana d. BINA
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19) A galvanometer basically is an instrument used to ____________________? a. detect current in a circuit b. measure current flowing through a circuit c. measure voltage across a circuit d. measure potential difference between two points in a circuit
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20) A wheat stone bridge is said to be balanced when____________________? a. maximum current flows through the galvanometer branch b. minimum current flows through the galvanometer branch c. potential difference across galvanometer branch is maximum d. potential difference across galvanometer branch is zero
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21) A particle of mass m charge q and speed V enters a uniform magnetic radius r. The radius r of the circle is_________________? a. independent mass m b. directly proportional to m c. directly proportional to q d. directly proportional to B
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22) If a current carrying solenoid is suspended freely it will__________________? a. be rotating b. come to rest in N-S direction c. vibrating like galvanometer needle d. comes to rest after rotation
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23) A current carrying conductor is placed in a uniform magnetic field parallel to it. The magnetic force experienced by the conductor is _____________________? a. F=1/B b. F=1/Bsinθ c. F/0 d. F=1/Bcosθ
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24) When a particle of charge q and mass m enters into a uniform magnetic field B moving with a velocity v perpendicular to the direction for the field it describes a circular path of radius___________________? a. R=qB/mV b. R=mV/qB c. R=qmV/B d. R=qmB/V
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25) A magnetic compass will be deflected if it is kept near a____________________? a. charge in motion b. charge at rest c. both d. none
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26) If the plane of the rectangular coil is parallel to the magnetic field (i.e radial magnetic field) the torque on the coil is_____________________? a. τ = NIAB cosφ b. τ = NIAB sinφ c. τ = NIAB tanφ d. τ = NIAB
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27) Magnetic flux and flux density are related by___________________? a. magnetic flux = flux density / area b. magnetic flux = flux density x area c. flux density = magnetic flux area d. flux density = magnetic flux x area
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28) The charged particle enters the uniform magnetic field in such a way that its initial velocity is not perpendicular to the field the orbit will be__________________? a. a circle b. a spiral c. an ellipse d. helix
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29) Value of permeability of free space in SI units is___________________? a. 4πx10-9 WbA-1m-1 b. 4πx10-7 WbA-1m-1 c. 4πx10-10 WbA-1m-1 d. 4πx10-8 WbA-1m-1
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30) The magnetic field strength of solenoid is__________________? a. B = μNI b. B = μN/I c. B = μnI d. Both B and C
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31) The deflection for 50 division of galvanometer is decreased to 25 divisions by shunt resistance of 12Ω. Galvanometer resistance is_____________? a. 18Ω b. 30Ω c. 24Ω d. 12Ω
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32) The sensitivity of a galvanometer is given by__________________? a. C/BAN b. CAN/B c. BAN/C d. ABC/N
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33) Minimum current required to produce a deflection of 1 mm on a scale at a distance of 1 meter is__________________? a. 0.1 A b. 1:00 AM c. current sensitivity d. 1 m A
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34) While measuring the unknown resistance the help of slide wire bridge a greatest accuracy can be achieved when__________________? a. a most sensitive galvanometer is used b. a steady voltage cell is used c. the balance point is close to the middle of the wire d. a high resistance box is used in one of its gap
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35) An ammeter measures the total current flowing through a circuit when it is connected__________________? a. in series with the circuit b. in parallel with circuit c. in series with any of the parallel resistances in the circuit d. in parallel with any of the series resistances in the circuit
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36) The effective way to increase the sensitivity of a moving coil galvanometer is to___________________? a. use a very long and fine suspension b. use a coil of very large area c. use a coil with very large number of turns d. use a very strong magnetic field
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37) When an electron moving with a uniform speed in a vacuum enters a magnetic field in a direction perpendicular to the field the subsequent path of the electron is ___________________? a. a straight line parallel to the field b. a parabola in a plane perpendicular to the field c. a circle in a plane perpendicular to the field d. a straight line along its initial direction
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38) Galvanometer is a very sensitive device with______________________? a. very low damping b. very high damping c. no damping at all d. radial field disintegration
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39) Heating a magnet will ____________________? a. weaken it b. strengthen it c. reverse its polarity d. demagnetize it completely
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40) A moving coil galvanometer of resistance 100? gives half scale deflection for a current of 20mA. What will be the potential difference across it ? a. 4 volt b. 5 volt c. 2 volt d. 0.4 volt
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