InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
The magnetic field lines in the middle of the current-carrying solenoid are :A. circlesB. spiralsC. parallel to the axis of the tubeD. perpendicular to the axis of the tube |
| Answer» Correct Answer - C | |
| 52. |
A soft iron bar is inserted inside a current-carrying solenoid. The magnetic field inside the solenoid :A. will decreaseB. will increaseC. will become zeroD. will remian the same |
| Answer» Correct Answer - B | |
| 53. |
Which of the following is most suitable for the core of electromagnets?A. soft ironB. brassC. aluminiumD. steel |
| Answer» Correct Answer - A | |
| 54. |
Which of the following has no effect on the sensitivity of a M.C.G. ?A. The current it measuresB. The thickness of the suspension fibreC. The magnetic filed of the permanet magnetD. Number of turns in the coil of the galvanometer |
| Answer» Correct Answer - A | |
| 55. |
For the maximum accuracy of M.C.G. deflection should beA. largeB. zeroC. infinityD. none of these |
| Answer» Correct Answer - A | |
| 56. |
The current that must flow through the coil of a galvanometre so as to produce a deflection of one division on its scale is calledA. microvolt sensitivityB. figure of meritC. charge sensitivityD. current sensitivity |
| Answer» Correct Answer - B | |
| 57. |
A soft iron core is palced at the centre of rectangular coil in M.C.G. becauseA. it increases magnetic fieldB. it decreases magnetic fieldC. more current to pass through the coilD. all of these |
| Answer» Correct Answer - A | |
| 58. |
The lamp and scale arrangement is used for the maeasurement of deflection inA. suspended coil type M.C.G.B. pivoted coil type M.C.G.C. tangent galvanometerD. potentiometer |
| Answer» Correct Answer - A | |
| 59. |
To make the field radial in a moving coil galvanometerA. the number of turns in the coil is increasedB. magnet is taken in the form of horse shoe typeC. poles are cylindrically cutD. coil is wound on aluminium frame |
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Answer» Correct Answer - C A moving coil galvanometer is based on the force acting on a conductor carrying a current placed in uniform magnetic induction. |
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| 60. |
In suspended coil type M.C.G. the coil is suspended in radial magnetic field by thin fibre of phosphor bronze becauseA. it has high potential constantB. it has low torsional constantC. negative torsional constantD. none of these |
| Answer» Correct Answer - B | |
| 61. |
In a moving coil galvanometer , a radial magnetic field is produced due to theA. concave pole pieces of the magnetB. rectangular coilC. iron coreD. mirror |
| Answer» Correct Answer - A | |
| 62. |
An arc of a circle of raduis `R` subtends an angle `(pi)/2` at the centre. It carriers a current `i`. The magnetic field at the centre will beA. `(mu_(0)i)/(2R)`B. `(mu_(0)i)/(8R)`C. `(mu_(0)i)/(4R)`D. `(2mu_(0)i)/(5R)` |
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Answer» Correct Answer - B Magnetic field at the centre of arc is given by `B=(mu_(0))/( 4pi)(theta i)/(r)=(mu_(0))/(4p)xx(pi)/(2)xx(i)/(R)=(mu_(0)i)/(8R)` |
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| 63. |
The moving coil galvanometer has 60 turns, a width of 2 cm and a length of 3 cm. It hangs in uniform magnetic field of 500 cgs unit. If the controlling couple, due to the twist in the suspension wire is 18 dyne cm, then the current flowing through it isA. `10^2 A`B. `10^-3 A`C. `10^-4 A`D. `3xx10^-5 A` |
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Answer» Correct Answer - B `i=(K)/(n AB)theta(because K, theta , n & A" are constant")` `therefore I prop 1//B rArr I_1 B_1=I_2B_2` `therefore I_2=(B_1)/(B_2)I_1=(4xx10^-3xx2)/(8xx10^-3)=1A` |
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| 64. |
Decreases in number of turns of coil in tangent galvanometer isA. to decrease sensitivityB. to decrease resistance of galvanometerC. to increase a field at centre of coilD. can not be predicted |
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Answer» Correct Answer - A `S=(cos^2theta)/(K)=(cos^2thetamu_0n)/(2a B_H)` `therefore` As n decreases S decreases . |
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| 65. |
Which of the following while in motion cannot be deflected by magnetic field?A. protonsB. cathode raysC. alpha particlesD. neutrons |
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Answer» Correct Answer - D The protons cathods rays and the alphs particles are charged particles so these are deflected by the magnetic field but neutrons have not any charge so these are not delfected by magnetic field |
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| 66. |
Tangent galvanometer mearusreA. capacitanceB. currentC. resistanceD. potential difference |
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Answer» Correct Answer - B Using tangent law we can find a relation `l prop tan theta` which clearly indicates that tangent galvanometer is an instrument used for detechtoon of electic current in a circuit |
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| 67. |
A long solenoid of length `L` has a mean diameter `D`. It has `n` layers of windings of `N` turns each. If it carries a current `‘i’` the magnetic field at its centre will beA. proportional to DB. inversely proportional to DC. independent of DD. proportional to L |
| Answer» Correct Answer - C | |
| 68. |
In moving coil galvanometer, the magnetic field used isA. uniformB. none uniformC. radialD. none of these |
| Answer» Correct Answer - C | |
| 69. |
The concave pole pieces of the strong magnets are used to produceA. uniform magnetic 9fieldB. non uniform magnetic fieldC. radial magnetic fieldD. all of these |
| Answer» Correct Answer - C | |
| 70. |
In radial magnetic field lines of force areA. parallelB. curvedC. along radiiD. none of these |
| Answer» Correct Answer - C | |
| 71. |
The magnetic field lines :A. intersect at right angles to one anotherB. intersect at an angle of `45^(@)` to each otherC. do not cross one anotherD. cross at an angle of `60^( @)` to one another. |
| Answer» Correct Answer - C | |
| 72. |
Which of the following is not attracted by a magnet ?A. steelB. cobaltC. brassD. nickel |
| Answer» Correct Answer - C | |
| 73. |
Draw magnetic field lines around a bar magnet.A. originate from the south pole and end at its north poleB. originate from the north pole and end at its east poleC. originate from the north pole and end at its south poleD. originate from the south pole and end at its west pole |
| Answer» Correct Answer - C | |
| 74. |
A strong bar magnet is placed vertically above a horizontal wooden board. The magnetic lines of force will be :A. only in horizontal plane around the magnetB. only in vertical plane around the magnetC. in horizontal as well as in vertical planes around the magnetD. in all the planes around the magnet |
| Answer» Correct Answer - D | |
| 75. |
In an electric motor, the direction of current in the coil changes once in each :A. two rotationsB. one rotationC. half rotationD. one-fourth rotation |
| Answer» Correct Answer - C | |
| 76. |
The coil of a sensitive M.C.G. swings too far on both sides. This movement can be quickly stopped byA. holding a magnet near the coilB. earthing the case of the galvanometerC. connecting a large resistance across the ends of the coilD. connecting a short length of copper wire across the ends of the coil |
| Answer» Correct Answer - D | |
| 77. |
Which of the following equation gives the current flowing through the coil of M.F.G. ?A. `I=(K theta)/(n AB)`B. `I=(n theta)/(KAB)`C. `I=(thetaA)/(KnB)`D. `I=(Btheta)/(n AB)` |
| Answer» Correct Answer - A | |
| 78. |
The current flowing through the coil of M.C.G.depends onA. torsional constant of suspension fibreB. area of the coilC. magnetic inductionD. all of these |
| Answer» Correct Answer - D | |
| 79. |
The magnetic field inside a solenoid is-A. non uniformB. zeroC. uniformD. infinity |
| Answer» Correct Answer - C | |
| 80. |
Which of the following correctly describes the magnetic field near a long straight wire?A. The field consists of straight lines perpendicular to the wireB. The field consists of straight lines parallel to the wireC. The field consists of radial lines, originating from the wireD. The field consists of concentric circles centered on the wire |
| Answer» Correct Answer - D | |
| 81. |
If a current flowing in a circular coil is in anticlockwise direction , then direction of magnetic field will beA. towards youB. away from youC. at an angle of `45^@`D. in parallel of the coil |
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Answer» Correct Answer - A According to right hand rule . |
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| 82. |
Field at one end of a solenoid isA. directly proportional to its lengthB. directly proportional to currentC. inversely proportional to total number of turnsD. inversely proportional to current |
| Answer» Correct Answer - B | |
| 83. |
The magnetic field intensity due to a long solenoid at its end isA. `mu_0 n I`B. `2 mu_0 n I`C. `mu_0 n I //2`D. `sqrt(mu_0 n I)` |
| Answer» Correct Answer - C | |
| 84. |
Which of the following correctly describes the magnetic field near a long straight wire?A. The field consists of straight lines perpendicular to the wireB. The field consists of straight lines parallel to the wire.C. The field consists of radial lines originating from the wire.D. The field consists of concentric circles entered on the wire. |
| Answer» Correct Answer - D | |
| 85. |
The direction of electric current in a solenoid when viewed from a particular end is anticlockwise, then this end of solenoid will be :A. north poleB. east poleC. south poleD. west pole |
| Answer» Correct Answer - A | |
| 86. |
A galvanometer has a resistance `100Omega` and gives a full scale deflection for a current of 0.1 A. It is to be converted into a voltmeter of range of 50 V. The resistance of voltmeter so formed isA. `400 Omega`B. `500 Omega`C. `200Omega`D. `80 Omega` |
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Answer» Correct Answer - B `(F_m)/(F_e)=(v^2)/(c^2)=((3xx10^5)^2)/((3xx10^8)^2)=10^-4`. |
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| 87. |
The conversion of a moving coil galvanometer into a voltmeter is done byA. a high resistance is connected in series with the galvanometer.B. a high resistance is connetec in parallel with the galvanometerC. a low resistance is connected in parallel with the galvanometerD. a low resistance is connected in series with the galvanometer |
| Answer» Correct Answer - B | |
| 88. |
To reduce the range of voltmeter, its resistance need to be reduced.A voltmeter has resistance `R_(0)` and range V. Which of the following resistance when connectyed in parallel will convert it into a voltmeter of range `V//n?A. `n R_0`B. `(n+1)R_0`C. `(n-1)R_0`D. none of these |
| Answer» Correct Answer - D | |
| 89. |
A voltmeter has resistance `R_0` and range V. What resistance should be connected in series with it to increase its range to n V ?A. `nR_0`B. `(n+1)R_0`C. `(n-1)R_0`D. `R_0//n` |
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Answer» Correct Answer - C When a resistance is connected in parallel , it will only reduce the resistance of the combination , but will not reduce the range. For reducing the range , the resistance in series with the galvanometer need to be reduced. This can not be achieved by connecting a resistance in parallel with the galvanometer. |
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| 90. |
The graph which represents the relation between the total resistance `R` of a multi range moving coil voltmeter and its full scale deflection A. B. C. D. |
| Answer» Correct Answer - B | |
| 91. |
For the measurement of potential difference, voltmeter is connectedA. in parallel with the circuitB. in series with the circuitC. in open circuitD. none of these |
| Answer» Correct Answer - A | |
| 92. |
To increase the range of voltmeter the series resistance should beA. increasedB. decreasedC. unchangedD. none of these |
| Answer» Correct Answer - A | |
| 93. |
Resistance of voltmeter is `10000Omega` to increase range of voltmeter from `25 V`, resistance connected in series isA. `990Omega`B. `9990Omega`C. `90000Omega`D. `90Omega` |
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Answer» Correct Answer - C `G=10000 Omega , n =(V)/(V_g)=(250)/(25)=10, R=?` ` R=G(n-1)=10000(10-1)` `=90000 Omega` . |
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| 94. |
A voltmeter of resistance `2000 Omega` reads 1 volt/division. The resistance required to be connected in series with voltmeter to make it to read 10 volt/divistion isA. `18 Omega`B. `180 Omega`C. `1800 Omega`D. `18000 Omega` |
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Answer» Correct Answer - D Let x be the total number of divisions on voltmeter. Thus , `V_g=x and V =10 x`. Now , `V_g=I_g G therefore I_g=V_g//G=x//2000` Thus , `R=(V)/(I_g)-G=(10x)/((x//2000))-2000` `=18000Omega` |
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| 95. |
A voltmeter having resistance of `50 × 10^(3)` ohm is used to measure the voltage in a circuit. To increase the range of measurement 3 times the additional series resistance required isA. `10^5 Omega`B. `1.5xx 10^5 Omega`C. `9xx10^5 Omega`D. `9xx 10^6 Omega` |
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Answer» Correct Answer - A `R=G(n-1)=50xx10^3(3-1)=10^5Omega` |
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| 96. |
A voltmeter can measure upto 25 volt and its resistance is `1000 Omega`. The resistance required to add with voltmeter to measure upto 250 volt will be-A. `90 Omega`B. `900 Omega`C. `9000 Omega`D. `90000 Omega` |
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Answer» Correct Answer - C `R=G(n-1)=1000(10-1)=9000Omega` |
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| 97. |
An ammeter of low range can be converted into an ammeter to higher range by connectingA. a high resistance in seriesB. a high resistance in parallelC. a low resistance in seriesD. a low resistance in parallel |
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Answer» Correct Answer - D It is not possible to decrease the range in the way. A series resistance can not change the current that will proudce full scale deflection. |
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| 98. |
A voltmeter has resistance of 2000 ohms and it can measure upto `2 V`. If we want ot increase its range to `10 V` then the, required resistance in series will beA. `4000 omega`B. `6000 omega`C. `7000 omega`D. `8000 omega` |
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Answer» Correct Answer - D As current `i_(g)=(2)/(2000)=1/1000A` Now for range `V=8V+2V=10V` `therefore` Resistance `R=(V)/(i_(g))-G` `=(10)/(1/1000)-2000=8000 omega` |
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| 99. |
An ammeter can be converted into voltmeter by connectingA. a low resistance in seriesB. a low resistance in parallelC. a high resistance in seriesD. a high resistance in parallel |
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Answer» Correct Answer - C `G=R_0, V_g=V,R=?, V=n V` `R=(V)/(I_g)-G=(V)/(V_g)-G=(V.G)/(V_g)-G` `therefore R= (n V.R)/(V)- R=R(n-1)` |
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| 100. |
A voltmeter reading upto 10 V has a resistance of`1000 Omega`. It can be converted into an ammeter reading up ot 10 A by connecting a shunt ofA. `1Omega`B. `0.1Omega`C. `2Omega`D. `0.2Omega` |
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Answer» Correct Answer - A `I_g =(V)/(R_v)=(10)/(1000)=(1)/(100)A` here `R_v=G` `therefore` Required shunt, `S=((I_g)/(I-I_g)).G=1 Omega` |
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