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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.
| 501. |
If a substance moves from stronger part to weaker part of the non uniform magnetic field than the substance isA. DiamagneticB. ParamagneticC. FerromagneticD. antiferromagnetic |
| Answer» Correct Answer - A | |
| 502. |
If a substance moves from stronger part to weaker part of the non uniform magnetic field than the substance isA. ElectromagneticB. DiamagneticC. ParamagneticD. Ferromagnetic |
| Answer» Correct Answer - B | |
| 503. |
A short bar magnet is placed in a horizontal plane with its axis in the magnetic merdian . Null points are found on its equitorial line (i.e., its normal bisector) at 12.5 G and the angle of dip is zero. (i) What is the total magnetic field at points on the axis of the magnet located by the same distance (12.5 cm) as the null-points from the centre? (ii) Locate the null points when the magnet is turned around by `180^(@)` . Assume that the length of the magnet is negligible as compared to the distance of the null-point from the centre of the magnet. |
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Answer» Correct Answer - (i)0.76 G (ii) 15.75 cm |
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| 504. |
The angle between the magnetic merdian and geographical merdian is calledA. Angle of dipB. Angle of declinationC. Magnetic momentD. Power of magnetic field |
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Answer» Correct Answer - B |
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| 505. |
Assertion: The permeability of a ferromagnetic material is independent of the magnetic field. Reason: Permeability of a material is a constant quantity.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertionC. f assertion is true but reason is false.D. If the assertion and r eason both are false |
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Answer» Correct Answer - D |
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| 506. |
Figures A and B show two iron nails each hanging from a bar magnet and a U shaped magnet.a. Identify the correct picture in A and B.b. Justify your answers. |
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Answer» a. A – Fig III B – Fig II b. In A two nails are hang from bar magnet. So the distant ends will be induced the same pole. So repulsion. But in U magnet at the distant opposite poles will be induced. So attraction. |
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| 507. |
Assertion: When a magnet is brought near iron nails, only translatory force act on it. Reason: The field due to magnet is generally uniformA. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertionC. f assertion is true but reason is false.D. If the assertion and r eason both are false |
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Answer» Correct Answer - D |
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| 508. |
A closely wound solenoid of 2000 turns and area of cross-section 1.6 × 10-4 m2 carrying a current of 4.0 A, is suspended through its centre allowing it to turn in a horizontal plane.(a) What is the magnetic moment associated with the solenoid?(b) What is the force and torque on the solenoid if a uniform horizontal magnetic field of 7.5 x 10-2 T is set up at an angle of 30° with the axis of the solenoid? |
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Answer» Number of turns of the solenoid = 2,000 (a) The magnetic moment of the solenoid, (b) τ - MB sin θ |
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| 509. |
When a bar magnet is placed at `90^(@)` to a uniform magnetic firld, it is acted upon by a couple which is maxium. For the couple to be half of the maximum. For the couple to be half of the maxiumum vlaue, at what angle should the magnet be inclined to the magnetic fiels `(B)`? |
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Answer» We know that, `tau=MB sin theta` If `theta=90^(@)` then `tau_(max)=MB`……`(1)` `(tau_(max))/(2)=MB sin theta` ……`(2)` From equations `(1)` and `(2)` `2=(1)/(sin theta)` or `sin theta=(1)/(2)` or `theta=30^(@)` |
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| 510. |
A bar magnet of magnetic moment `M_(1)` is suspended by a wire in a magnetic field. The upper end of the wire is rotated through `180^(@)`, then the magnet rotated through `45^(@)`. Under similar conditions another magnetic of magnetic moment `M_(2)` is rotated through `30^(0)`. Then find the ratio of `M_(1)&M_(2)`. |
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Answer» `C(alpha-theta)=MB sin theta` For first magnet, `C(180-45)=M_(1)B sin 45^(@)` For second magnet, `C(180-30)=M_(2)B sin 30^(@)` …….`(2)` Diving equation `(1)` by equation `(2)` `(135)/(150)=(M_(1))/(M_(2))xxsqrt2=rArr(M_(1))/(M_(2))=(9)/(10sqrt2)` |
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| 511. |
The magnetic moment of a magnet `(15cmxx2cmxx1cm) is 1.2A-m^(2)`. Calculate its intensity of magnetisationA. `3xx10^(4) A//m`B. `4xx 10^(4) A//m`C. `3 xx 10^(-4) A//m`D. `4 xx 10^(-4) A//m` |
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Answer» Correct Answer - B `M=1.2Am^(2),I=?` `I=(M)/(V)=(1.2)/(15xx2xx1xx10^(-6))` `=4xx10^(4)A//m` |
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| 512. |
An iron rod is subjected to cycles of magnetisation at the rate of `50Hz`. Given the density of the rod is `8xx10^(3)kg//m^(3)` and specific heat is `0.11xx10^(-3)calxxkg^(@)C`. The rise in temperature per minute, if the area enclosed by the `B-H` loop corresponds to energy of `10^(-2)J` is (Assume there is no radiation losses)A. `78^(@)C`B. `88^(@)C`C. `8.1^(@)C`D. none of these |
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Answer» Correct Answer - C `50xx60xx10^(-2)=dx xx0.11xx10^(-3)xx4.2xxDeltat` |
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| 513. |
If M is magnetic moment developed in the material having volume V,then intensity of magnetisation is given by expession.A. MVB. M/VC. `Msqrt(V)`D. `M/sqrt(V)` |
| Answer» Correct Answer - B | |
| 514. |
The ratio of magnetisation I to the magnetic field intensity H isA. SusceptibilityB. PermeabilityC. PermittivityD. All of those |
| Answer» Correct Answer - A | |
| 515. |
A thin iron rod is cut into `10` equal parts parallel to its length. The intensity of magnetisation of each piece will be…..A. `(1)/(10)th` of initial valueB. `10` times initial valueC. does not changeD. becomes half |
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Answer» Correct Answer - C `I` is inderpendent of dimensions |
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| 516. |
A place where the vertical components of Earth’s magnetic field is zero has the angle of dip equal to (A) 0° (B) 45° (C) 60° (D) 90° |
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Answer» Correct answer is (A) 0° |
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| 517. |
The relative permeability of ferromagnetic substance is:(a) μr > 1(b) μr >> 1(c) μr = 1(d) μr = 0 |
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Answer» (b) μr >> 1 |
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| 518. |
If a magnetic substance is kept in a magnetic field, then which of the following is thrown out?A. ParamagneticB. ferromagneticC. DiamagneticD. Anti-ferromagnetic |
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Answer» Correct Answer - C Magnetic substance when kept in a magnetic field is feebly repelled or thrown out , if the substance is diamagnetic . |
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| 519. |
The angle between the geographical axis and the magnetic axis is `17^(@)`, then why does the value of angle of declination change from place to place ? |
| Answer» Difference between geographical axis and geographical meridian. Difference between magnetic axis and magnetic meridian. | |
| 520. |
The magnetism of a bar magnet is due toA. the earthB. cosmic raysC. the spin motion of electronsD. pressure of big magnet inside the earth |
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Answer» Correct Answer - C The magnetism of the magnet is due to the spin motion of electrons. Each electron in an atom is revolving in an orbit around the nucleus . The revolving electron is equivalent to a tiny loop of current . Therefore , it possesses some orbital magnetic dipole moment M = current ` xx ` area of the loop . In addition to the orbital motion , every electron is assumed to have a spin motion around its axis . Therefore , another dipole magnetic moment called spin magnet `M_s` is also associated with electron . The vector sum of `M_l` and `M_s` provides the net magnetic dipole moment M to the atom . `M_s` is much greater than `M_l` , hence magnetism of magnet is due to spin motion of electrons . |
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| 521. |
A bar magnet and a soft iron bar AB are placed close to each other as shown below Mark the polarity of induced magnetism in the soft iron bar with the help of lines of force. Explain by giving reasons for the polarity marked by you. |
| Answer» Map the magnetic lines of force in the magnetic field of a bar magnet . What is the direction of magnetic lines of force in the soft iron rod ? Identify the magnetic poles by using the direction of magnetic lines of force inside the iron bar. | |
| 522. |
The unit of magnetic moment isA. `Wb//m`B. `W b m^(2)`C. A.mD. `A.m^(2)` |
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Answer» Correct Answer - D |
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| 523. |
The earth can be considerd as a huge bar magnet. |
| Answer» Correct Answer - T | |
| 524. |
A magnetic compass does not show any particular direction at the magnetic poles. |
| Answer» Correct Answer - T | |
| 525. |
If the strength of the magnetic field is increased by `21%` the frequency of a magnetic needle oscillating in the field.A. increased by `10%`B. Decreases by `10%`C. Increases by `11%`D. Decreased by `21%` |
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Answer» Correct Answer - A `nalphasqrt(B)` `((n_(2))/(n_(1))-1)xx100=(sqrt((B_(2))/(B_(1))-1))xx100` |
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| 526. |
The magnetic compass is not useful for navigation near the magnetic poles becauseA. The magnetic field near the poles is zeroB. The magnetic field near the poles is almost verticalC. At low temperature, the compass needle looses its magnetic propertiesD. Neither of the above |
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Answer» Correct Answer - B |
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| 527. |
A bar magnet has a magnetic moment equal to `65xx10^(-5)` wever `x` metre. It is suspended in a magnetic field which has a magnetic induction `(B)` equal to `8pixx10^(-4)` tesla. The magnet vibrates with a period of vibration equal to `15`seconds. The moment of inertia of the magnet is:A. `9xx10^(-13)kg m^(2)`B. `11.25xx10^(-13)kg m^(2)`C. `5.62xx10^(-13)kg m^(2)`D. `0.57xx10^(-13)kg m^(2)` |
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Answer» Correct Answer - A `I=(MBT^(2))/(4pi^(2))` |
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| 528. |
The dipole moment of a short bar magnet is `1.25 A-m^(2)`. The magnetic field on its axis at a distance of 0.5 metre from the centre of the magnet isA. `1.0xx10^(-4)"Newton"//amp-meter`B. `4xx10^(-2)"Newton"//amp-meter`C. `2xx10^(-6)"Newton"//amp-meter`D. `6.64xx10^(-8)"Newton"//amp-meter` |
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Answer» Correct Answer - C |
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| 529. |
The permanent magnet is made fron which one of the following substances?A. DiamagneticB. ParamagneticC. FerromagneticD. Electromagnetic |
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Answer» Correct Answer - C |
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| 530. |
The S.I. unit of magnetic permeability isA. `Am^(-1)`B. `Am`C. Henry ` m^(-1)`D. No unit, it is a dimensionless number |
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Answer» Correct Answer - C |
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| 531. |
A permanent magnet –A. Attracts all substancesB. Attracts only magnetic substancesC. Attracts magnetic substances and repels all non-magnetic substancesD. Attracts non-magnetic substances and repels magnetic substances |
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Answer» Correct Answer - B |
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| 532. |
A permanent magnet in the shape of a thin cylinder of length `10cm` has `M=10^6A//m`. Calculate the magnetisation current `I_M`. (Here M is the intensity of magnetisation).A. `10^(5)A`B. `10^(3)A`C. `1A`D. `2A` |
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Answer» Correct Answer - A Given, `M` (intensity of magnetisation) `=1(length)=10 cm=10xx10^(-2)m=0.1m` and `I_(m)=` magnetisation current We know that `M=(I_(M))/(1)` `rArr I_(M)=Mxx1` `=10^(6)xx0.1=10^(5)A` |
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| 533. |
In a permanent magnet at room temperature.A. magnetic moment of each molecule is zeroB. the indivudial molecules have non-zero magnetic moments which are all perfectly alignedC. domains are all perfectly alignedD. domains are all perfectly aligned |
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Answer» Correct Answer - C Alignment of domains depends upon temperature. |
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| 534. |
Statement-1 : Gauss theorem is not applicable in magnetism. Statement-2 : Mono magnetic pole does not exist.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertionC. f assertion is true but reason is false.D. If the assertion and r eason both are false |
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Answer» Correct Answer - A |
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| 535. |
State Right hand thumb rule. |
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Answer» If we curl the fingers of right hand in the direction of current in the loop, then the stretched thumb gives the direction of the mag netic moment associated with the loop |
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| 536. |
Write down the concept of Maxwell’s right hand cork screw rule. |
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Answer» This rule is used to determine the direction of the magnetic field. If we rotate a right-handed screw using a screw driver, then the direction of current is same as the direction in which screw advances and the direction of rotation of the screw gives the direction of the magnetic field. |
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| 537. |
Define in terms of Current Sensitivity of a galvanometer. |
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Answer» It is defined as the deflection produced per unit current flowing through it. Is = \(\frac{θ}{I}\) = \(\frac{NAB}{K}\) ⇒Is = \(\frac{1}{G}\) |
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| 538. |
Tangent galvanometer works on the principle of ……… |
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Answer» Tangent galvanometer works on the principle of Tangent Law. |
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| 539. |
The tangent law is applied in ……… |
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Answer» The tangent law is applied in Tangent. |
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| 540. |
What is meant by hysteresis? |
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Answer» The phenomenon of lagging of magnetic induction behind the magnetising field is called hysteresis. Hysteresis means Tagging behind’. |
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| 541. |
The earth’s magnetic field varies from point to point in space. Does it also change with time? If so, on what time scale does it change appreciably? |
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Answer» Yes, it changes with time. After a few hundred years, the earth’s magnetic field undergoes an appreciable change. |
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| 542. |
A magnet oscillating in a horizontal plane has a time period of 2 seconds at a place where the angle of dip is `30^(@)` and 3 seconds at another place where the angle of dip is `60^(@)`. The retio of resultant magnetic field at the two places isA. `(4sqrt(3))/(7)`B. `(4)/(9sqrt(3))`C. `(9)/(sqrt(3))`D. `(9)/(sqrt(3))` |
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Answer» Correct Answer - C |
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| 543. |
A magnetic dipole is under the influence of two magnetic fields. The angle between the two field directions is `60^(@)` and one of the fields has a magnitude of `1.2xx10^(-2)T`. If the dipole comes to stable equilibrium at an angle of `15^(0)` with this field, what is the magnitude of the other field?A. `1.39xx1010^(-3)T`B. `2.39xx10^(-3)T`C. `3.39xx10^(-3)T`D. `4.39xx10^(-3)` |
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Answer» Correct Answer - D `MB_(1)sin15^(@)=MB_(2)Sin60^(@)` `B_(1)=1.2xx10^(-2)` |
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| 544. |
Magnetic dip was measured at various places on earth in one of the following countries . It was found to be zero inA. PakistanB. BrazilC. ScotlandD. Canada |
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Answer» Correct Answer - B In Brazil , magnetic inclination was zero. |
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| 545. |
A magnetic dipole is under the inflluence of two magnetic fields having an angle of `120^(0)` between them. One of the fields has a magnitude `1.2xx10^(-2)T`. If the dipole comes to stable equilibrium at an angle of `30^(0)` with this field, then magnitude of the other field isA. `8.484xx10^(-2)T`B. `0.6xx10^(-2)T`C. `4.242xx10^(-3)T`D. `4.242xx10^(-5)T` |
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Answer» Correct Answer - B `B_(1) sin 30^(@)=B_(2) sin 90^(@)` |
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| 546. |
Two identical short bar magnets, each having magnetic moment `M`, are placed a distance of `2d` apart with axes perpendicular to each other in a horizontal plane. The magnetic induction at a point midway between them isA. `(mu_(0))/(4pi).(sqrt2)(M)/(d^(3))`B. `(mu_(0))/(4pi).(sqrt3)(M)/(d^(3))`C. `(mu_(0))/(4pi).(M)/(d^(3))`D. `(mui_(0))/(4pi).(sqrt5)(M)/(d^(3))` |
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Answer» Correct Answer - D `B=sqrt(B_(axial)^(2)+B_(eq)^(2)` |
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| 547. |
Magnets `A` and `B` are geometrically similar but the magnetic moment of `A` is twice that of `B`. If `T_(1)` and `T_(2)` be the time periods of the oscillation when their like poles and unlike poles are kept togather respectively, then `T_(1)/T_(2)` will beA. `(1)/(3)`B. `(1)/(2)`C. `(1)/(sqrt(3))`D. `sqrt(3)` |
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Answer» Correct Answer - C |
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| 548. |
Curie-Weiss law is obeyed by iron at a temperature….A. Below Curie temperatureB. Above Curie temperatureC. At Curie temperature onlyD. At all temperatures |
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Answer» Correct Answer - B |
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| 549. |
Curie-Weiss law is obeyed by iron at a temperature….A. at all temperaturesB. above the curie temperatureC. below the curie temperatureD. at the curie temperature |
| Answer» Correct Answer - B | |
| 550. |
Liquid oxygen remains suspended between two pole faces of a magnet because it isA. DiamagneticB. ParamagneticC. FerromagneticD. Antiferromagnetic |
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Answer» Correct Answer - B |
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