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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.
| 1. |
A wires PQRS carrying a current I runs along three edges of a cube of side l as shown in figure. There exists a uniform magnetic field of magnitude B along one of the sides of cube. The magnitude of the force acting on the wire is A. zeroB. `sqrt(3)IB`C. `sqrt(2I) lB`D. 2Ilb |
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Answer» Correct Answer - C |
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| 2. |
Three long straight wires `A`, `B` and `C` are carrying current as shown in figure. Then the resultant force on `B` is directed A. towards AB. towards CC. perpendicular to the plane of paper and outwardD. Perpendicular to the plane of paper and inward |
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Answer» Correct Answer - A |
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| 3. |
Assertion Two infinitely long wires `A` and `B` carry unequal currents both in inward direction. Then, there is only point (excluding the ponts at infinity), where net magnetic field is zero. Reason That point liews between points `A` abnd `B`.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 not correct explanation of Assertion.C. If Assertion is true but Reason is false.D. If Assertion is false but Reason is true. |
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Answer» Correct Answer - b |
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| 4. |
A wire of length `L metre ` , carrying a current `I `ampere is bent in the form of a circle . The magnitude of its magnetic moment is …………. ` MKS units ` .A. `(L^(2)I^(2))/(4pi)`B. `(LI)/(4pi)`C. `(L^(2)I)/(4pi)`D. `(LI)/(4pi)` |
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Answer» Correct Answer - c |
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| 5. |
Figure shows, three long straight wires parallel and equally speed with identical currents. Then, the force acting on each wire due to the other is A. `F_(a) gt F_(b) gt F_(c)`B. `F_(b) gt F_(c) gt F_(a)`C. `F_(c) gt F_(a) gt F_(b)`D. `F_(b) gt F_(a) gt F_(c)` |
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Answer» Correct Answer - B |
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| 6. |
Two infinitely long, thin, insulated, straight wires lie in the x-y plane along the x- and y- axis respectively. Each wire carries a current I, respectively in the positive x-direction and positive y-direction. The magnetic field will be zero at all points on the straight line:A. y = xB. y = -xC. y = x-1D. y = -x+1 |
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Answer» Correct Answer - A |
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| 7. |
Two straight wires each 10 cm long are parallel to one another and separated by 2 cm. when the current flowing in them is 30 A and 40 A respectively then the force experienced by either of the wires isA. `1.2xx10^(-3)N`B. `12xx10^(-3)N`C. `11.2xx10^(-3)N`D. `10.2x10^(-3)N` |
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Answer» Correct Answer - a |
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| 8. |
A long wire carries a steady curent . It is bent into a circle of one turn and the magnetic field at the centre of the coil is `B`. It is then bent into a circular loop of `n` turns. The magnetic field at the centre of the coil will beA. nBB. `n^(2)B`C. `2nB`D. `2n^(2)B` |
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Answer» Correct Answer - b |
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| 9. |
An infinitely long conductor is bent into a circle as shown in figure. It carries a current I ampere and the radius of loop is R metre. The magnetic induction at the centre of loop is A. `(mu_(0)2I)/(4piR)(pi + 1)`B. `(mu_(0)2I)/(4piR)(pi - 1)`C. `(mu_(0)I)/(8piR)(pi + 1)`D. zero |
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Answer» Correct Answer - A |
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| 10. |
Assertion three infinitely long current carrying wires have equal currents and they are equally spaced. The magnitude of magnetic force on all three is same. Reason Net force on wire-2 is zero. |
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Answer» Correct Answer - d |
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| 11. |
A large metal sheet carries an electric current along its surface. Current per unit length is `lambda` . Magnetic field near the metal sheet is. A. `lambdamu_(0)`B. `(lambdamu_(0))/(2)`C. `(lambdamu_(0))/(2pi)`D. `(mu_(0))/(2pilambda)` |
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Answer» Correct Answer - B |
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| 12. |
A conductor of length 5 cm is moved paralllel to itself with a speed of `2m//s`, perpendicular to a uniform magnetic field of `10^(-3) Wb//m^(2).` the induced emf generated isA. `2xx10^(-3) V`B. `1xx10^(-3) V`C. `1xx10^(-4)V`D. `2xx10^(-4) V` |
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Answer» Correct Answer - c |
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| 13. |
A square current carrying loop abcd is palced near an infinitely long another current carrying wire ef. Now, match the following two columns. |
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Answer» Correct Answer - `A to p; B to q,s; C to q,s; D to q,s` |
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| 14. |
The coil of a moving coil galvanometer has an effective area of 4xx10^(-2)m^(2)`. It is suspended in a magnetic field of `5xx10^(-2)` Wb `m^(-2)`. If deflection in the galvanometer coil is 0.2 rad when a current of 5 mA is passed through it, thenA. torsional constant is `5xx10^(-5)N-m" rad"^(-1)`B. current sensitivity is `40 rad` `A^(-1)`C. torsional constant is `3xx10^(-3)` `N-m` `" rad"^(-1)`D. current sensitivity is `40 deg` `A^(-1)` |
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Answer» Correct Answer - A::B |
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| 15. |
Two protons are projected simultaneously from a fixed point with the same velocity v into a region, magnetic there exists a uniform magnetic field. The magnetic field strength at B and it si perpendicular to the initial direction of v. One proton starts at time t=0 and another proton at `t = (pim)/(2qB)`. The separation between them at time `t = (pim)/(qB)` (where, m and q are the mass and charge of proton), will be approximatelyA. `2(mv)/(qB)`B. `(sqrt(2)mv)/(qB)`C. `(mv)/(qB)`D. `(mv)/(2qB)` |
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Answer» Correct Answer - B |
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| 16. |
Assertion A charged particle is rotating in a circle. Then magnetic field (B) at centre of circle and magnetic moment (M) produced by motion of charged particle are parallel to each other. Reason M and B are always parallel to each other. |
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Answer» Correct Answer - c |
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| 17. |
A charged particle is rotating in uniform circular motion in a uniform magnetic field . Let r= radius of circule, v= speed of particle k = kinetic energy, a= magnitude of acceleration , p= magnitude of linear momentum, `q/m = alpha`=specific charge and `omega=` angular speed. then match the following two columns. |
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Answer» Correct Answer - `A to p; B to q; C to p; D to q` |
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| 18. |
The intensity of uniform magnetic field between poles of a magnetic is H. If a straight wire carrying current is placed in between the poles. The direction of force on the wire is- A. perpendicular to both current and magnetic fieldB. in the direction of currentC. same as magnetic fieldD. in all directions |
| Answer» Correct Answer - A | |
| 19. |
A beam of protons enters a uniform magnetic field of 0.3T with velocity of `4xx10^5m//s` in a direction making an angle of `60^(@)` with the direction of magnetic field. The path of motion of the particle will beA. circularB. Straight lineC. SpiralD. helical |
| Answer» Correct Answer - D | |
| 20. |
A current loop in a magnetic fieldA. experiences a torque whether the field is uniform or non-uniform in all orientationsB. can be in equilibrium in one orientationsC. can be equilibrium in two orientations, both the equilibrium states are unstableD. can be in equilibrium in two orientations one stable while the other is unstable |
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Answer» Correct Answer - d |
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| 21. |
There is a ring of radius r having linear charge density `lambda` and rotating with a uniform angular velocity `omega.` the magnetic field produced by this ring at its own centre would beA. `(lambda omega^(2))/(2-mu_(0))`B. `(mu_(0)lambda^(2)omega)/(sqrt2)`C. `(mu_(0)lambda omega)/(2)`D. `(mu_(0)lambda)/(2omega^(2))` |
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Answer» Correct Answer - c |
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| 22. |
A proton and helium nucleus are shot into a magnetic field at right angles to the field with same kinetic energy. Then the ratio of their radii isA. `1:1`B. `1:2`C. `2:1`D. `1:4` |
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Answer» Correct Answer - a |
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| 23. |
A metal rod of length l cuts across a uniform magnetic field B with a velocity v. If the resistance of the circuit of which the rod forms a part is r, then the force required to move the rod isA. `(B^(2)l^(2)v)/(r)`B. `(Blv)/(r)`C. `(B^(2)lv)/(r)`D. `(Blv^(2))/(r)` |
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Answer» Correct Answer - a |
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| 24. |
Two particles A and B having equal charges `+6C`, after being accelerated through the same potential differences, enter a region of uniform magnetic field and describe circular paths of radii `2cm` and `3cm` respectively. The ratio of mass of A to that of B isA. `1//3`B. `1//2`C. `4//9`D. `9//5` |
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Answer» Correct Answer - c |
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| 25. |
Assertion An `alpha-`particle and a deuteron having same kinetic energy enter in a uniform magnetic field perpendicular to the field. Then, radius of circular path of `alpha-`particle will be more. Reason `(q)/(m)` ratio of an `alpha-`particle is more than the `(q)/(m)` ratio of a deuteron.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 not correct explanation of Assertion.C. If Assertion is true but Reason is false.D. If Assertion is false but Reason is true. |
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Answer» Correct Answer - d |
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| 26. |
Two charged particles have charges and masses in the ratio `2:3` and `1:4` respectively. If they enter a uniform magnetic field and move with the same velocity then the ratio of their respective time periods of revolutions isA. `3:8`B. `1:4`C. `3:5`D. `1:6` |
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Answer» Correct Answer - a |
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| 27. |
A particle of mass m and having a positive charge q is projected from origin with speed `v_(0)` along the positive X-axis in a magnetic field B = `-B_(0)hatK`, where `B_(0)` is a positive constant. If the particle passes through (0,y,0), then y is equal toA. `-(2mv_(0))/(qB_(0))`B. `(mv_(0))/(qB)`C. `-(mv_(0))/(qB)`D. `(2mv_(0))/(qB_(0))` |
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Answer» Correct Answer - D |
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| 28. |
If a charged particle at rest experiences no electromagnetic force,A. electron field must be zeroB. magnetic field must be zeroC. electron field must be zeroD. None of above |
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Answer» Correct Answer - A |
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| 29. |
A charge q is moving with a velocity `v_(1)=1hati` m/s at a point in a magentic field and experiences a force `F=q[-hatj+1hatk]` N. If the charge is moving with a voloctiy `v_(2)=hatj` m/s at the same point then it experiences a force `F_(2)=q(1hati-1hatk)` N. The magnetic induction B at that point isA. `(hat(i)+hat(j)+hat(k))Wb//m^(2)`B. `(hat(i)-hat(j)+hat(k))Wb//m^(2)`C. `(-hat(i)+hat(j)-hat(k))Wb//m^(2)`D. `(hat(i)+hat(j)-hat(k))Wb//m^(2)` |
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Answer» Correct Answer - A |
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| 30. |
A circular flexible loop of wire of radius r carrying a current I is placed in a uniform magnetic field B . If B is doubled, then tension in the loopA. remains unchangedB. is doubledC. is halvedD. becomes 4 times |
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Answer» Correct Answer - B |
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| 31. |
A charged particle P leaves the origin with speed `v=v_0` at some inclination with the x-axis. There is a uniform magnetic field B along the x-axis. P strikes a fixed target T on the x-axis for a minimum value of `B=B_0`. P will also strike T ifA. `B = 2B_(0), v = 2v_(0)`B. `B = 2B_(0), v = v_(0)`C. Both are correctD. Both are wrong |
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Answer» Correct Answer - A |
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| 32. |
Two concentric circular coils of ten turns each are situated in the same plane. Their radii are `20` and `40 cm` and they carry respectively `0.2` and `0.3` ampere current in opposite direction. The magnetic field in `Wb//m^(3)` at the centre isA. `(35//4)mu_(0)`B. `(mu_(0)//80)`C. `(7//80)mu_(0)`D. `(25//2)mu_(0)` |
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Answer» Correct Answer - B |
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| 33. |
Two identical coils carry equal currents have a common centre and their planes are at right angles to each other. The ratio of the magnitude of the resulatant magnetic field at the centre and the field due to one coil isA. `2:1`B. `1:1`C. `1:sqrt(2)`D. `sqrt(2):1` |
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Answer» Correct Answer - C |
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| 34. |
The rectangular coil of area A is in a field B. Find the torque about the Z-axis when the coil lies in the position shown and carries a current I. A. IAB in negative Z-axisB. IAB in positive Z-axisC. 2IAM in positive Z-axisD. 2IAB in negative Z-axis |
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Answer» Correct Answer - B |
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| 35. |
The use of Helmholtz coils is to produce-A. uniform magnetic fieldB. non-uniform magnetic fieldC. varying magnetic fieldD. zero magnetic field |
| Answer» Correct Answer - A | |
| 36. |
Due to the flow of current in a circular loop of radius `R`, the magnetic induction produced at the centre of the loop is `B`. The magnetic moment of the loop is (`mu_(0)`=permeability constant)A. `(BR^(2))/(2pi mu_(0))`B. `(2piBR^(2))/(mu_(0))`C. `(BR^(2))/( 2pi mu_(0))`D. `(2pi BR^(2))/(mu_(0))` |
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Answer» Correct Answer - b |
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| 37. |
A conducting loop is placed in a uniform magnetic field with its plane perpendicular to the field with its plane perpendicular to the field. An emf is induced in the loop if (i) it is translated (ii) it is rotated about its axis (iii) it is rotated about a diameter (iv) it is deformedA. it is translated parallel to itselfB. it is rotated about one of its diametersC. it is rotated about its own axis which is parallel to the fieldD. the loop is deformed from the original shape |
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Answer» Correct Answer - b |
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| 38. |
A toroid having 200 turns carries a current of 1A. The average radius of the toroid is 10 cm. the magnetic field at any point in the open space inside the toroid isA. `4xx10^(-3)T`B. zeroC. `0.5xx10^(-3)T`D. `2xx10^(-3)T` |
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Answer» Correct Answer - b |
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| 39. |
The magnetic field due to a current carrying circular loop of radius 3 cm at a point on the axis at a distance of 4cm from the centre is `54muT`. What will be its vlue at the centre of loop?A. `200 mu T`B. `250 mu T`C. `125 mu T`D. `75 mu T` |
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Answer» Correct Answer - b |
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| 40. |
The magnetic field inside a solenoid is-A. infinteB. zeroC. uniformD. non-uniform |
| Answer» Correct Answer - C | |
| 41. |
The correct curve between the magnetic induction (B) along the axis of a along solenoid due to current flow i in it and distance x from one end is -A. B. C. D. |
| Answer» Correct Answer - A | |
| 42. |
A solenoid has length `0.4cm`, radius 1 cm and 400 turns of wire. If a current fo 5 A is passed through this solenoid, then what is the magnetic field inside the solenoid?A. `6.28xx10^(-4)T`B. `6.28xx10^(-3)T`C. `6.28xx10^(-7)T`D. `6.28xx10^(-6)T` |
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Answer» Correct Answer - b |
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| 43. |
The magnetic field at a point on the axis of a long solenoid having 5 turns per cm length when a current of 0.8 A flows through it isA. `5.024xx10^(-8) Wb//m^(2)`B. `6.024xx10^(-8)Wb//m^(2)`C. `7.024xx10^(-8) Wb//m^(2)`D. `8.024xx10^(-8) Wb//m^(2)` |
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Answer» Correct Answer - a |
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| 44. |
A proton is projected with a speed of `3X10^6 ms ^(-1)` horizontally from est to west. A uniform magnetic field `vec B` of strength `2.0X10^(-3)` T exists in the vertically upward direction(a) find the force on the proton just after it is projected. (b) what is the acceleration produced?A. `11.6 xx 10^(11) m//s^(2)`B. `17.4xx10^(11)m//s`C. `5.8xx10^(11)m//s^(2)`D. `2.9xx10^(11)m//s^(2)` |
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Answer» Correct Answer - c |
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| 45. |
In a cyclotron, a charged particleA. undergoes acceleration all the timeB. speeds up between the does because of the magnetic fielsC. speeds up in a deeD. slows down within a dee and speeds up between dees |
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Answer» Correct Answer - A |
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| 46. |
Biot-Savart law indicates that the moving electrons (velocity `vecv` ) produce a magnetic field `vecB` such thatA. B is perpendicular to vB. B is parallel to vC. it obeys inverse cube lawD. it is along the line joining the electron and point of observation |
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Answer» Correct Answer - A |
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| 47. |
A current flows in a conductor from east to west. The direction of the magnetic field at a points above the conductor isA. towards northB. towards southC. towards eastD. towards west |
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Answer» Correct Answer - A |
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| 48. |
A non - popular loop of conducting wire carrying a current `I` is placed as shown in the figure . Each of the straighrt sections of the loop is of the length ` 2a`. The magnetic field due to this loop at the point `P(a, 0 ,a)` points in the direction A. `(1)/(sqrt(2))(-hat(j)+hat(k))`B. `(1)/(sqrt(3))(-hat(j)+hat(k)+hat(i))`C. `(1)/(sqrt(3))(hat(i)+hat(j)+hat(k))`D. `(1)/(sqrt(2))(hat(i)+hat(k))` |
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Answer» Correct Answer - D |
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| 49. |
When the number of turns in a toroidal coil is doubled, then the value of magnetic flux density will becomes-A. four timesB. eight timesC. halfD. double |
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Answer» Correct Answer - D `Bxx2piR=mu_(0) xxN.i` `B=(mu_(0).i)/(2piR).N` `B prop N` So the magnetic field will be double. |
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| 50. |
A current of `0.1 A` circulates around a coil of 100 turns and having a radius equal to `5 cm`. The magnetic field set up at the centre of the coil is (`mu_(0)=4pixx10^(-7)` weber/amper-metre)A. `5pixx10^(-5)T`B. `8pixx10^(-5)T`C. `4pixx10^(-5)T`D. `2pixx10^(-5)T` |
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Answer» Correct Answer - C |
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