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.
| 301. |
When two parallel wires carrying current l and 2l in same direction are placed at a distance d apart, the ratio of force per unit length acting upon the wire due to other isA. `1 : 1`B. `1 : 2`C. `2 : 1`D. None of these |
| Answer» Correct Answer - A | |
| 302. |
Suppose that a proton travelling in vacuum with velocity `V_(1)` at right angles to a uniform magnetic field experiences twice the force that an `alpha`-particle experiences when it is travelling along into same path with velocity `V_(2)`. The ratio `(V_(1))/(V_(2))` isA. 0.5B. 1C. 2D. 4 |
| Answer» Correct Answer - D | |
| 303. |
The coils made of same material in two moving coil galvanometer have their area in the ratio of `2:3` and number of turns in the ratio `4:5` . These two coils carry the same current and are situated in the same field. The deflections produced by these two coils willl be in the ratio ofA. `8:15`B. `15:8`C. `8:1`D. `1:4` |
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Answer» Correct Answer - 1 `tau theta=BAIN` |
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| 304. |
A current of `10^(-5)A` produced a deflection of `10^(@)` in a moving coil galvanometer . A current of `10^(-6)amp` in the same galvanometer produces a deflection of `1^(@)`A. `0.1^(@)`B. `10^(@)`C. `(1//100)^(@)`D. |
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Answer» Correct Answer - 1 `theta alphaI` |
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| 305. |
A voltmeter which can measure 2 V isconstructed by using a galvanometer of resistance `12 Omega` and that produces maximum deflection for the current of 2mA. Then the resistance R is A. `888 Omega`B. `988 Omega`C. `898 Omega`D. `999 Omega` |
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Answer» Correct Answer - B `R=V/I_(g)-G` Putting `V=2 V, I_(g)= 2 mA= 2 xx 10^(-3) A, G=12 Omega`. `therefore R=2/(2 xx 10^(-3)) -12 = 1000 -12=988 Omega` |
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| 306. |
Assertion: When a magnetic dipole is placed in a non-uniform magnetic field, only a torque acts on the dipole. Reason: Force would also acts on dipole if magnetic field were uniform.A. If both assertion and reason are true and reason is the correct explanation of assertion.B. If both assertion and reason are true but reason is the correct explanation of assertion.C. If assertion is true but reason is falseD. If both assertion and reason are false. |
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Answer» Correct Answer - D In a non-uniform magnetic field, both torque and net force act on the dipole. If magnetic field were uniform, net force on dipole would be zero.. |
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| 307. |
Write two reasons, why a galvanometer cannot be used as such to measure current in a given circuit.A. If both assertion and reason are true and reason is the correct explanation of assertion.B. If both assertion and reason are true but reason is the correct explanation of assertion.C. If assertion is true but reason is falseD. If both assertion and reason are false. |
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Answer» Correct Answer - A Galvanometer is a very sensitive device, it gives a full-scale deflection for current of the order of micro ampere. Also for measuring current the galvanometer has to be connected in series,and as it has a large resistance, this will change the value ofhte current in the circuit. To overcomes these difficulties one attaches a small resistance called shunt resistance in parallel with the galvanometer coil. |
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| 308. |
`Assertion:` current sensitivity of a galvanometer is directly proportional to the current through the coil. `Reason:` Voltage sensitivity is inversely proportional to voltage.A. If both assertion and reason are true and reason is the correct explanation of assertion.B. If both assertion and reason are true but reason is the correct explanation of assertion.C. If assertion is true but reason is falseD. If both assertion and reason are false. |
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Answer» Correct Answer - D Increasing the current sensitivity may not necessarily increase the voltage sensitivity. |
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| 309. |
If the current sensitivity of a galvanometer is doubled, then its voltage sensitivity will beA. doubledB. halvedC. unchangedD. four times |
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Answer» Correct Answer - C Current sensitivity of galvanometer is deflection per unit current i.e. `(phi)/(I)=(NAB)/(k)" …(i)"` Similarly voltage sensitivity is deflection per unit voltage i.e. `(phi)/(V)=((NAB)/(k))(I)/(V)=((NAB)/(k))=(1)/(R)" ...(ii)"` From (i) and (ii) Voltage sensitivity `="current sensitivity"xx(1)/("resistance")` Now if current sensitivity is doubled, then the resistance in the circuit will also be doubled since it is proportional to the length of the wire, then voltge sensitivity `=(2xx"current sensitivity")xx(1)/((2xx"resistance"))` `="(current sensitivity)"xx(1)/("(resistance)")` Hence, voltage sensitivity will remain unchanged. |
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| 310. |
A galvanometer of resistance `70 Omega`, is converted to an ammeter by a shunt resistance `r_(3) = 0.03 Omega`. The value of its resistance will becomeA. `0.025 Omega`B. `0.022Omega`C. `0.035Omega`D. `0.030Omega` |
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Answer» Correct Answer - D `R=(R_(G)r_(s))/(R_(G) + r_(s))` Here, `R_(G) = 70 Omega, r_(s) = 0.03 Omega` `therefore R=(70 xx 0.03)/(70 +0.03) = 0.02998 = 0.03 Omega` |
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| 311. |
A galvaometer of coil resistance `100Omega` is connected to a shunt of resistance `10Omega`. The current throught the galvanometer is `i_(10` , the current through the shunt is `i_(2)` and the total current into the combination is `i_(3)`, then the ratio `i_(1):i_(2):i_(3)` isA. `1:10:11`B. `10:1:11`C. `11:10:1`D. `10:11:1` |
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Answer» Correct Answer - 1 `Ig=(S)/(G+S)(I)` |
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| 312. |
The resistance of a galvanometer is `100Omega`. A shunt of `5 Omega` is connected to it to convert it into an ammeter. The internal resistance of the ammeter isA. `5.2Omega`B. `4.8Omega`C. `4.6Omega`D. `4.2Omega` |
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Answer» Correct Answer - 2 `R_(eff)=(GS)/(G+S)` |
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| 313. |
The range of voltmeter of resistance `300 Omega` is 5 V. The resistance to be connected to convert it into an ammeter of range 5 A isA. ` 1 Omega "in series"`B. `1 Omega "in parallel"`C. `0.1 Omega "in series"`D. `0.1 Omega "in parallel"` |
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Answer» Correct Answer - B A voltmeter is a galvanometer having a high resistance connected in series with it. The current through the galvanometer is `I_(g) = (5V)/(300 Omega) = 1/60 A` An ammeter is a galvanometer having a low resistance connected in parallel with it. The shunt resistance S is determined from `I_(g)/(I-I_(g)) = S/G` where `G=3000 Omega` (Given) For `I=5A`, we get `(1//60)/(5-(1//60)) = S/300 rArr S= 1Omega` |
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| 314. |
The radial magnetic field is used in a suspended coil galvanometer to provideA. a uniform torque on the coilB. maximum torque on the coil in all positionsC. a uniform and maximum torque in all positions of the coilD. a non uniform torque on the coil |
| Answer» Correct Answer - 1 | |
| 315. |
To increase the range of an ammeter, we need to connect a suitableA. low resistance in parallelB. low resistance in seriesC. high resistance in parallelD. high resistance in series. |
| Answer» Correct Answer - 1 | |
| 316. |
Among the following the false statement isA. ammeter is connected in series and maximum current flows through isB. voltmeter is connected in parallel and potential is maximumC. ammeter is connected in series and current through it is negligibleD. voltmeter is connected in parallel and current through it is negligible. |
| Answer» Correct Answer - 3 | |
| 317. |
A voltmeter has a resistance `G` and range `V`. Calculate the resistance to be used in series with it to extend its range to `nV`.A. `ng`B. `g(n-1)`C. `(g)/(n)`D. `(g)/((n-1))` |
| Answer» Correct Answer - 2 | |
| 318. |
In an electrical circuit containing a source of `emf` and a load resistance, the voltmeter is connected by mistake in series with the load across the source and ammeter is connected parallel to the load. Then which meter burns outA. ammeterB. voltmeterC. both ammeter and voltmeter in seriesD. neither ammeter nor voltmeter |
| Answer» Correct Answer - 4 | |
| 319. |
A long straight wire of radius `a` carries a steady current `i`. The current is uniformly distributed across its cross section. The ratio of the magnetis field at `(a)//(2) and (2a)` isA. `1//4`B. 4C. 1D. `1//2` |
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Answer» Correct Answer - 3 `B_(1)=(mu_(0))/(2pi)(ir_(1))/(R)B_(2)=(mu_(0))/(2pi)(i)/(r_(2))` |
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| 320. |
A spiral loop has inner radius 10 cm and outer radius 20 cm and carries current 1A in each turn. The total no. of turn in loop is 100. A small rectangular loop of area `2 cm^(2)` carries current 0.05 A is placed at the centre of loop. If magnitude of potential energy of rectangular loop is `(x mu_(0)Ln2)/(400)J`. then find out the value of x |
| Answer» Correct Answer - 2 | |
| 321. |
A star shaped loop ( with `l=` length of each section ) carries current i. Magnetic field at the centroid of the loop is A. `(3mu_(0)i)/(pi l)`B. `(3 mu_(0)i)/(2pi l)`C. `(3-sqrt(3))(mu_(0)i)/(pil)`D. `(3+sqrt(3))(mu_(0)i)/(pil)` |
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Answer» Correct Answer - C `r=(sqrt(3)l)/(2)` `B=6[(mu_(0))/(4pi)(i)/(r)(sin 60^(@)+sin60^(@))]` `-6[(mu_(0))/(4pi).(i)/(r)(sin30^(@)+sin30^(@))]` `=6xx(mu_(0))/(4pi).(i)/(r)(sqrt(3)-1)` `=6xx(mu_(0))/(4pi).(i)/(((sqrt(3)l)/(2)))(sqrt(3)-1)` `=(3-sqrt(3))[(mu_(0)i)/(pi l)]` |
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| 322. |
A cell of negligible internal resistance is connected to a tangent galvanometer and the deflection produced is `30^(@)`. If theree such cells are connected in series and the combination is connected to the same galvanometer, the deflection will beA. `30^(@)`B. `60^(@)`C. `90^(@)`D. `45^(@)` |
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Answer» Correct Answer - B `(I_(1))/(3I_(1))=(tan30^(@))/(tantheta_(2))` |
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| 323. |
An electric charge in uniformmotion producesA. an electric field onlyB. a magnetic field onlyC. both electric and magnetic fieldD. no such field at all |
| Answer» Correct Answer - 3 | |
| 324. |
The reduction factor of a tangent galvanometer may be defined as the current passing through it to produce a deflection ofA. `90^(@)`B. `45^(@)`C. `30^(@)`D. `60^(@)` |
| Answer» Correct Answer - 2 | |
| 325. |
Three long straight conductors are kept perpendicular to the plane of paper. Currents `2A,3A` are passing through the two conductors into the plane of paper in first two conductors and `5A` current passes through thirst conductor, directed out of the paper. A closed loop encloses the conductors, then the value of `oint bar(B). bar(dl)` over the closed loop is `(` assume current into the paper as negative and out of the paper as positive `)`A. `2 mu_(0)`B. zeroC. `- mu_(0)`D. `+ mu_(0)` |
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Answer» Correct Answer - 2 `ointB.dl=mu_(0)i` |
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| 326. |
A tangen galvanometer of reduction factor `1A` is placed with plane of its coil perpendicular to the magnetic meridian when a current of `1A` is passed through it. The deflection produced isA. `45^(@)`B. ZeroC. `30^(@)`D. `60^(@)` |
| Answer» Correct Answer - 2 | |
| 327. |
A tangent galvanometer propertly adjusted gives a deflection of `30^(@)` when a certain current is passed through it. When the current is changed, then it gives a deflection of `45^(@)`. The ratio of the currents in the two cases isA. `2:3`B. `1:sqrt(2)`C. `1:sqrt(3)`D. `sqrt(3):1` |
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Answer» Correct Answer - 3 `(I_(1))/(I_(2))=(tan theta_(1))/(tan theta_(2))` |
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| 328. |
Two long straight conductors carry currents `4 A` and` 2A` into the plane of paper. A circular path is imagined to be enclosing these currents. The value of `oint bar(B).bar(dl) isA. `6 mu_(0)`B. `7 mu_(0)`C. `5 mu_(0)`D. `2 mu_(0)` |
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Answer» Correct Answer - 1 `mu_(0)sumi` |
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| 329. |
Two long concetric cylindrical conductors of radii a and b `(b lt a)` are maintained at a potential difference V and carry equal and opposite currents l. Show that an electron with a particular velocity u parallel to the axis may travel underivated in the evacuated region between the conductors, and calculate u when a = 50 mm, b = 2.0 mm, V = 50 V and l = 100 A. It is also possible for the electron to travel in a helical path. By regarding such a path as the combination of a circular motion perpendicular to the axis with a steady velocity parallel to the axis, indicate without detailed mathematics how this comes about. |
| Answer» For the electron to go undeviated `u = (2pi V)/(mu_(0)l In ((a)/(b)))` | |
| 330. |
In a propertly adjusted tangent galvanometer, the deflection for `1A` current is found to `30^(@)`. Now the coil is turned through `90^(@)` about the vertical axis, the deflection for the same current will beA. `60^(@)`B. `30^(@)`C. `90^(@)`D. `0^(@)` |
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Answer» Correct Answer - 4 `B=B_(H)Tan theta` |
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| 331. |
Two parallel conductors `A` and `B` of equal lengths carry currents `I` and `10 I`, respectively, in the same direction. ThenA. A and B will repel each other with same forceB. A and B will attract each other with same forceC. A will attract B, but B will repel AD. A and B will attract each other with different forces |
| Answer» Correct Answer - B | |
| 332. |
A rectangular coil of size `3xx3cm` consisting of 100 turns caries `0.1A`. If it produces a deflection `10^(0)`, in a field of induction `0.1T`, the couple per unit twist isA. `9xx10^(-2)N-m//` DegreeB. `9xx10^(-5)N-m//` DegreeC. `9xx10^(-5)N-m// rad`D. ``0.9N-m//`Degree |
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Answer» Correct Answer - 2 `c theta=Ni AB` |
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| 333. |
A and B are two conductors carrying a current i in the same direction x and y are two electron beams moving in the same direction. There will be A. Repulsion between A and B, attraction between x and yB. Atraction between A and B, repulsion between x and yC. Repulsion between A and B and also x and yD. Attraction between A and B also x and y |
| Answer» Correct Answer - B | |
| 334. |
Two long parallel copper wires carry currents of `5 A` each in opposite directions. If the wires are separated by a distance of ` 0.5m` , then the force between the two wires isA. `10^(-5)N//m` attractiveB. `10^(-5)N//m` repulsiveC. `2xx10^(-6)N//m` attractiveD. `2xx10^(-5)N//m` repulsive. |
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Answer» Correct Answer - 2 `F=(mu_(0)I_(1)I_(2))/(2pir)l` |
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| 335. |
Two straight parallel wires carry currents of `200 mA` and `1A` in opposite direction. If the wires are `20cm` apart, the distance of the neutral point from the `1A` wire is `(` in cm )A. 5B. 15C. 20D. 25 |
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Answer» Correct Answer - 4 `x=(d)/((i_(2))/(i_(1))-1)` |
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| 336. |
Two long parallel copper wires carry current of 5A each in opposite directions. If the wires are separated by a distance distance of 0.5m, then the force per unit length between the two wires isA. `10^(-5)N//m`, attractiveB. `10^(-5) N//m` repulsiveC. `2 xx 10^(-5) N//m`, attractiveD. `2 xx 10^(-5) N//m`, repulsive |
| Answer» Correct Answer - B | |
| 337. |
Two parallel conductor carrying `5A` each , repel with a force of `0.25Nm^(-1)`. The distance between them isA. `4xx10^(-5)m`B. `3xx10^(-5)m`C. `2xx10^(-5)m`D. `1xx10^(-5)m` |
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Answer» Correct Answer - C `F=(mu_(0))/(2pi)(i_(1)i_(2))/(r)xxl` |
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