Magnetism and Matter Questions and Answers

2 A linear magnet of magnetic moment M is bend in arc as shown in the given figure The magnetic moment of arc is Muy Me 1 M 3 3M T 60 2 3M 5A 4 Zero E Ma e y

5 A long straight wire of radius a carries a steady current I The current is uniformly distributed over its cross section The ratio of the magnetic fields B and B at radial distances and 2 a respectively from the a NEET 2016 2 axis of the wire is a 2 c 4 b 1 d 1 o

4 A is false But Ris 39 When a bar magnet is suspended freely in a uniform magnetic field identify the correct statements a The magnet experiences only couple and undergoes only rotatory motion b The direction of torque is along the suspension wire c The magnitude of torque is maximum when the magnet is normal to the field direction 1 only a and care correct 2 only a and b are correct 3 only b and care correct

23 The appropriate M versus magnetization magnetising field H curve for a paramagnetic substance is most a A b B c C d D MA 0 C A B D H

A beam of protons is moving horizontally towards you As it approaches it passes through a magnetic field directed downward The beam deflects 3 Does not deflect 1 To your left side 2 To your right side orporate Office B 58 Goal Building Budha Colony Patna 1 4 Nothing can be said

sometimes more than A bar magnet is made to fall through a long vertic copper tube The speed v of the magnet as function of time t is best represented by 1 a 2 b 3 c 1 d V d b a C

7 An iron rod of susceptibility 599 is subjected to a magnetising field of 1200 A m 1 The permeability of the material of the rod is No 4 x 10 7 Tm A 1 2 4mx 10 5 Tm A 1 2 4mx 10 7 Tm A 1 2 3 2 4mx 10 4 Tm A 1 4 8 0 x 10 5 Tm A 1

7 In the given figure net magnetic field at O will be a c 0 0 O a 0 i 2 oi 4 37 2 0 4 7 2a 0 3a 0 b d Hoi 37 4 7 Moi 4 7 3m

2 A bar magnet of magnetic moment M is placed at a distance D with its axis along positive X axis Likewise second bar mag net of magnetic moment M is placed at a distance 2D on positive Y axis and perpen dicular to it as shown in the figure The mag nitude of magnetic field at the origin is B HOM 4 D Assume D l where l is the length of magnets The value of a must be b N 2D OD 15 S N S X 17 9

In the figure shown a current I is established in the long straight wire AB Another wire CD carrying current I i placed in the plane of the paper The line joining the ends of this wire is perpendicular to the wire AB The resultant force on the wire CD is 1 zero towards positive y axis Bi K X C A 2 towards negative x axis 4 none of these

3 perpendicular to its velocity 4 zero A proton a deuteron and an a particle having the same kinetic energy are moving in circular trajectories in a constant magnetic field If rp ra and r denote respectively the radii of the trajectories of these particles then d T Tp r d Ta 3 I Id p r 4 r Id ra P 2 Ta rd p Two very long straight parallel wires carry steady currents I and I respectively The distance between the

A bar magnet of magnetic moment M and moment of inetria I is freely suspended such that the magnetic axial line is in the direction of magnetic meridian If the magnet is displaced by a very small angle 0 angular acceleration is AIIMS 2018 magnetic induction of earth s horizontal field is B MB 0 I X4 MO 3 IB H 2 4 IB 0 M 10 MB in mubstance of susceptibility 3 x 10 is placed in a magnetising field of 4 x 10 Am Then the intensity AIIMS 2018

3 curved path of electron is more curved than that of prot 4 path of proton is more curved 2 com If a current is passed through a spring then the spring will 1 expand Land carrying currents i and i respectively are inclined at an angle 9 to each other What is the force on a small in figure due to the magnetic field of wire 1 AIEEE 2002 3 remain same compress 4 none of these AIEEE 2002

1 2R R 2 R 2R 3 R 2R The magnetic needle of a tangent galvanometer is deflected by an angle 30 due to a magnet The horizontal componen of earth s magnetic field is 0 34 x 10 T along the plane of the coil The intensity of magnetic field of magnet is 1 1 96 x 10 T 2 1 96 x 10 5 T 4 1 96 x 105 T 3 1 96 x 10 T RPMT 2009 length of a long solenoid If 4A currents is flowing in the solenoid t

Four wires of equal length are bent in the form of four loops P Q R and S These are suspended in a uniform magnetic field and same current is passed in them The maximum torque will act on

PROPERTIES OF MA When a small magnetising field H is applied to a magnetic material the intensity of magnetisation is proportional 1 H 2 H 2 3 H 4 H How does the magnetic susceptibility X of a paramagnetic material change with absolute temperatue T 1 T

The value of earth magnetic field BH 0 3 gauss In this magnetic field a magnet is oscillating with 5 oscillation min To increase the oscillation of magnet upto 10 oscillation min The value of earth magnetic field increased by Question Type Single Correct Type 1 0 3 gauss 2 0 6 gauss 3 0 9 gauss 4 0 12 gauss

Statement I The ferromagnetic property depends on temperature At high temperature ferromagnet becomes paramagnet Statement II At high temperature the domain wall area of a ferromagnetic substance increases In the light of the above statements choose the most appropriate answer from the options given below A Statement I is false but Statement II is true B Statement I is true but Statement II is false Both Statement I and Statement II are false D Both Statement I and Statement II are true

1500 turns per metre and an iron core of 1100 is kept inside it 2 A current flows in the coil of solenoid If core is heated beyond curie temperature then 1 The H and B fields in the solenoid reduces to zero 2 The H and B fields in the solenoid remains unchanged 3 The H field in the solenoid is nearly unchanged but B field decreases significantly 4 The B field in the solenoid is nearly unchanged but H field decreases significantly

2 Two similar nature magnetic poles of strength 16 A m and 64 A m are placed at a distance of 120 cm in air At which point on the line joining the two poles the force on another unit north pole will be zero 1 0 8 m from 64 Am 2 0 8 m from 16 Am 3 0 4 m from 64 Am 4 0 6 from 64 Am

1 Time period of vibration of a bar magnet in vibration magnetometer is T If the magnet is cut into n identical parts such that length of each part is equal to length of original magnet then time period of vibration of one part in the vibration magnetometer is 2 3 n T 2 nT 4 T 57 Due to in the e intens position 1 9 2 4 4

39 A small square loop of wire of side I is placed inside a large square loop of side L L I If the loops are coplanar and their centres coincide the mutual inductance of the system is directly proportional to 1 7 3 2 4 L 10 mH

The magnetic susceptibility of a substance at room temperature is 0 0002 The susceptibility when the temperature increased by 2 C will be 0 0001 0 0002 0 0002 0 0005

bimetallic strip is made of aluminium and steel aal asteel then on hea e strip will Aluminium Steel ORemain straight Get twisted O Will bend with aluminum on concave side Will bond with otool or novo pido

A current i 3 36 1 2t x 10 2 A increase at a steady rate in a loop straight wire A very small circular loop of radius 10 3 m has its plane parallel to the wire and is placed at a distance of 1m of wire The induced emf in loop is A 134 4 X 10 15 V B 13 44 T X 10 15 V C 1 344 x 10 15 V D 0 1344 x 10 15 V 1m

10 What the number that measures an object s resistance to being deformed elastically when stress is applied to it a Elastic modulus b Plastic modulus c Poisson s ratio d Stress modulus

If a magnetic field H 3a 4a A m exists at a point in free space the magnetic flux density at that point is bold representations are vectors a 3a 2a wb m b 3 768a 5 024a wb m c 3 768a 5 024a uwb m d 3 768a 5 024a wb m

A solenoid wound over a rectangular frame If all the linear dimensions of the frame are increased by a facto libih 4 0 5 H 3 and the number of turns per unit length remains the same the self inductance increased by a factor of 1 3 2 9 3 27 4 63 7 A coil of inductance 2 H has a current of 5 8 A The flux in weber through the coil is 1 0 29 2 2 9 8 R L D C CIRCUIT Case I Current Growth 3 3 12 sir ye increased by a factor mai 4 11 6 confusion ho rhi hai ye smiha do

A proton and a deuteron moving with equal kinetic energies enter perpendicularly in a region of magnetic field B If r T and r are the radii of circular paths taken by proton and deuteron respectively the ratio T 1 2 2 2 3 2 2 4 2 would be 5552

The following questions consist of two statements each printed as Assertion and Reason While answering these questions you are required to choose any one of the following responses 11 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 a correct explanation of the Assertion C If Assertion is true but the Reason is false D If both Assertion and Reason are false Assertion Ampere s law is to Biot Savart law what Gauss s law is to Coulomb s law Reason Both Ampere s and Gauss s law relate a physical quantity on the periphery or boundary magnetic or electric field to another physical quantity namely the source in the interior current or charge We also note that Ampere s circuital law holds for steady currents which do not fluctuate with time a A b B c C d D

e Draw appropriate electric field lines on the figure below for the three cases shown These should represent the electric field due to 1 a single positive point charge 2 two very long oppositely charged parallel conducting sheets and 3 an electric dipole Be sure to label the direction of the field

Ans a 0 032 Nm so that it is free to rotate in the horizontal plane Find the position of equilibrium of the system with respect to each other One magnet has a magnetic moment 4 times that of the other This arrangement is pivoted 32 Two magnets of equal mass are joined together at their centres so that their axes are at right angles to the magnetic meridian Ans Angles with the meridian are 14 03 and 75 97 33 A steel rod of mass 0 15 x 10 3 kg is suspended from its centre of gravity If the rod is magnetised s din anglais 200 ded so that it remains horizontal in the magnetic

component of earth s field is 0 4 x 10 4 T 28 A magnet makes 12 oscillations per minute in the earth s magnetic field alone and 15 oscillations per minute when a short magnet with its axis horizontal and its south pole pointing north is placed with its centre 20 x 10 2 m directly above the oscillating magnet Find the magnetic moment of the short magnet Given BH 0 36 10 4 T 29 Two an I S C 04 Ans 0 81 J T have pole strength 60 Am When they cannot

A bar magnet with its north N and south S poles is initially moving to the left along the axis of fixed circular conducting loop as shown A current is induced in the loop As seen from the magnet side lq er 0 0 of T 0 MICH S N 1 runs clockwise and acceleration of magnet is towards left 2 runs counterclockwise and acceleration of magnet is towards right 3 runs clockwise and acceleration of magnet is towards right 4 runs counterclockwise and acceleration of

Given BH 0 36 x 10 4 T 29 Two small identical magnets are 8 x 10 2 m long and have pole strength 60 Am When they cannot rotate it is possible to make one float 6 x 10 2 m above the other Find the force which the lower magnet exerts on the upper one J E E 00 Ans 0 16 N netic fields The angle between the field directions 30 A magnetic dipole is

Two geometrically identical bar magnets having their identical poles are together and allowed to magnetic moments 4M and 5M are joined such that oscillate in a magnetic field It is found that time the polarity of one of the magnet is reversed and taken in completing three oscillation is 3 second If the combination is again made to oscillate in same magnetic field then time period of oscillation will be 1 9 sec 3 3 3 sec 2 3 sec 1 4 3 sec

7 A bar magnet has dimensions of 25 cm 10 cm anc 5 cm If length of magnet is 25 cm and its pol strength is 200 x 10 3 Am then intensity magnetisation of magnet is 1 40 A m 2 6 25 A m 4 80 A m 3 62 5 A m

agnetic field If shape of the coil is varied witho ut chang ing its perimeter and current through it torque act ing on it will be 1 same for any shape of coil 2 maximum for a square shape

The galavanometer consists of a coil with 10 te many turns wound on a cylinderical soft iron core When a current flows through the coil a torque acts on it This torque is given by t NIAB The magnetic torque NIAB tends to rotate the coil by angle o A spring provides a counter torque ko that balances the magnetic torque The current sensitivity of the galvanometer is the deflection per unit current Statement 1 Two galvanometers with identical construction but one with core of greater permeability will have lesser current sensitivity Statement 2 Greater is the permeability of iron core greater is magnetic field 1 Statement I is true Statement II is true Statement II is the correct explanation of Statement I 2 Statement I is true Statement II is true Statement II is not the correct explanation of Statement I 3 Statement I is true Statement II is false 1 Statement I is false Statement II is true NIABUS al R 13 2 1 NIA fun 2 3 4 fur

4 Any value Two identical bar magnets each of same length and magnetic moment one bent into a semicircular are placed as shown If the angle made by the resultant magnetic moment with the magnetic axis of semicircular arc is 0 then 1 tane 1 3 tane 1 N SS 0 63 2 tane 1 57 4 tan0 0 5 2M E N 17 ja 9 12 Ho 3M 4 r 2M 4M 2

1 New Zealand is situated in southern hemisphere 44 and Russia is situated in Northern hemisphere The angle of dip at New Zealand and Russia are 8 and 8 respectively then 1 8 up 8 up 2 8 down 8 up 3 8 up 8 down 4 8 down 8 down fera SH 1 8 2 8 3 8 4 8

4 All of the above If a magnet of pole strength m is cut into four 2 parts such that length and width of each part is half that of initial one then pole strength of each part 1 m 4 2 m 3 m 8 4 m 2 3 NA GIRAN 31 12 1 m 4

12 Relative permeability of iron is 5500 then its 12 magnetic susceptibility is 2 5501 4 zero 1 5500 3 5499 gracht 1 55 3 5

55 Identify the wrong statement regarding the earth s magnetism a b c d the declination is smaller at higher latitudes and greater near the equator In most of the northern hemisphere the north pole of the dip needle tilts downwards If the needle is only capable of moving in horizontal plane it can point along any direction near the poles of the earth The angle of dip at a place on the earth gives the direction of earth s magnetic field 1

Mark the CORRECT option A vertical plane containing the vertical axis orthogonal to ground and the longitude is called the geographic meridian O Geographic meridian and magnetic meridian for earth are always same at a point The dip circle is simply a compass needle pivoted about a fixed vertical axis and free to move in a horizontal plane O There is a bar magnet buried deep inside earth s interior which gives rise to earth s magnetic field

An assembly placed on a frictionless floor consists of two light bars A and B four light springs and a block C of mass m Stiffness of each springs is shown in the figure Initially all the springs are relaxed and the bars are parallel to each other The bar A is pulled from its midpoint towards the right by a force that increases gradually from zero When the block acquires an acceleration a by what amount will the separation between the bars increase k ENGEDHETENDE FAR ALPERESENTES k B C SENDESENTO A Pull

The maximum intensity of fringes in young s double slit experiment is If one of slit is closed the intensity of that point becomes lo The correct relation is 0 1 10 O 1 2 O 1 4 O There is no relation between and

A material when heated suddenly changes its magnetic property at a particular temperature and above this temperature its susceptibility is found to be inversely proportional to the absolute temperature The material may be Only one correct answer A Ferromagnetic B Diamagnetic C Paramagnetic

A solid body floating in water has 1 of its volume immersed in it What fraction of its volume 5th

6 At a place in magnetic meridian magnetic needle bends 30 from horizontal If earth s magnetic field at this place is 2 G then vertical component and horizontal component of earth s magnetic field respectively are a 10T 2x10 T b 10 T 3x10 T c 3x10 T 10 T d 3x10 1 2x10 T