Magnetism and Matter Questions and Answers

A thin bar magnet when placed in a magnetic field of magnitude 2 T performs 10 oscillations per second The magnet is now divided into three equal parts by cutting perpendicular to its axis and kept in a magnetic field of magnitude 4 T Now each part would oscillate with a frequency of O 40 Hz O16 Hz o 302 HI 0 23 Hz

Biot Savart law indicates that the moving electrons velocity v produce a magnetic field B such that OB is parallel to v Oit obeys inverse cube law it is along the line joining the electron and point of observation B is perpendicular to v

Current I is uniformly distributed across cross sectional area of hollow cylindrical conductor of inner radius R and outer radius 3R Magnetic field at distance 2R from axis of cylindrical conductor is 2 1 MoI 2TR 5 I 36TR 3 Ho I 32 R 4 3 oI 32 R

temperature above its Curie temperature the material 1 Is permanently magnetized 2 Remains ferromagnetic 3 Behaves like a diamagnetic material

The angle of declination is defined as the angle between the geographic north and 1 South shown by a compass needle 2 Geographic south 3 North shown by a compass needle 4 Magnetic needle of dip circle

A paramagnetic material had a magnetic field intensity of 105 A m If the susceptibility of the material at room temperature is 4 5 103 calculate the flux density in the material 12 61 x 104 Wb m 12 61 x 10 2 Wb m 12 61 x 10 3 Wb m 12 61 x 10 1 Wb m Test time

A circular coil of radius 10 cm has a concentric and coplanar circular coil of radius 0 01 cm The approximate value of the coefficient of mutual inductance of the coils wil be 2x 10 13 H 4 x 10 6 H 8 x 10 11 H 6 x 10 8 H

48 Two short magnets of magnetic moment 1000 Am are placed as shown at the corners of square of side 10cm The net magnetic induction at P is 1 0 1T 3 0 3T 10cm 10cm N 2 0 2T 4 0 4T

1 A bar magnet of magnetic dipole moment 10 Am is in stable equilibrium The work done to rotate the magnet through 60 in a magnetic field of 0 2T is 1 2 2J 3 1J 4 43 2 Time period of a thin bar magnet in uniform magnetic field is T Now the magnet is cut into two identical halves so that its length becomes half and time period of each small magnet in the same magnetic field is T The ratio of T and T is 1 2 2 2 3 2 2 3 If and are the apparent angles of dip observed elquestionper 4 4 1 in two vertical planes at right angles to each other and the true angle of dip is at that place then 4 1 tan tan tan 2 2 tan cot cot 02 3 cot2 cot cot 2 4 cos cos cos 2 Isoclinic lines are 1 Line joining places of equal angle of dip 2 Line joining places of zero angle of dip Telegr 3 Line joining places of equal angle of declination 4 Line joining places of zero angle of declination 5 Magnetic field inside substance is B and that in free space is Bo then for B Bo the substance is 1 a paramagnetic 2 a diamagnetic 3 a ferromagnetic 4 1 and 2 both are possible 3 Magnetic susceptibility of a paramagnetic substance is plotted against absolute temperature T The correct graph is 1 8 2 A 4 7 A short bar magnet has point A and B along axis at a distance of 24 cm and 48 cm from cen on the opposite sides Ratio of magnitude magnetic fields at these points will be 1 2 2 8 3 3 A magnet when suspended at an angle of 30 magnetic meridian the dip needle makes an ang 45 with horizontal The dip angle measured magnetic meridian will be 1 tan 2 tan 3 3 2 3 tan 2 4 tan 1 2

field at onent at place is 47 Magnetism and Matter The intensity of magnetisation 1 of paramagnetic material is related to absolute temperature T as 1 IT 2 1 x T 3 1 7 7 4 1 7

In a vertical plane inclined at an angle 60 with magnetic meridian the angle of dip is found to be 45 If is true angle of dip at that place then the value of tans is 1 0 5 3 0 75 2 2 4 1 33 1

49 In a tangent galvanometer a current of 0 1A produces a deflection of 30 The current required uestion produce deflection of 60 is 1 0 2A 3 0 4A 50 vibration 2 0 3A 4 0 5A identical

A thin magnetic needle oscillate in the horizontal plane with a time period of 2 0 sec If the needle is broken in 4 equal parts perpendicular to its length then time period of each part will be 1 0 5 sec 3 1 5 sec 2 1 05 sec 4 2 0 sec neet Telegram

Magnetic field inside substance is B and that in free space is B then for B Bo the substance is 1 a paramagnetic 2 a diamagnetic 3 a ferromagnetic 4 1 and 2 esible

Aakash Institute 21 Two magnets each of dipole moment Pm and length are placed perpendicularly as shown in figure The magnitude of dipole moment of the combination will be 1 2Pm 2 2 Pm Pm 3 N N S

4 Magnetic field is only due to the current element passing through the loop 69 A particle of charge q and mass m moves in a circular orbit of radius r with angular speed o The ratio of the magnitude of its magnetic moment to that of its angular momentum depends on 1 w and q 3 q and m 2 o q and m 4 and m

18 A magnet of length L and of pole strength m is cut into half breadth wise and half lengthwise and thus four identical pieces are obtained Magnetic etquestion moment of each piece will become 1 3 mL 8 mL 2 mL 1 ml

0 29 View In English The dip at a place is 6 For measuring it the axis of the dip needle is perpendicular to the magnetic meridian If the axis of the dip needle makes angle 8 with the magnetic meridian the apparent dip will be given by tan which is equal to 1 2 3 4 orrect Answer 4 atus unattempted tan cos 8 tan 6 sec B tan o sin 0 tan 5 cosec

3 106Hz 4 104Hz 77 Find the ratio of magnetic dipole moment to angular momentum of an electron in a hydrogen like atom in ground state 1 E 2 e 2m

The x y plane is the boundary between free space and a magnetic material with relative permeability The magnetic field in the free space is Bi Bk The magnetic field in the magnetic material is A Bi Bk C B i B k YSIC B Bi H Bk D Bi B k

Aakash Institute 28 The magnitude of magnetic moment of a rectangular loop ABCD Fig 1 carrying a current i is M EF is the perpendicular bisector of side AB and DC If the loop is folded about EF Fig 2 to convert it into two mutually perpendicular planes AFED and ECBF then the magnitude of new magnetic moment will be IA 2 D 1 M N M M 3 2 TI F E Fig 1 B C A E Fig 2 B C

A loop carrying current i lies in x y plane as shown in the figure The loop is made of 4 semicircular portions The magnetic moment of the current loop is 1 aik homogeneous non 2 2x 1 a ik 1 7 a k

View In English A dip circle shows an apparent dip of 45 at a place where the true dip is 30 If the dip circle is rotated through 90 what apparent dip will it show 1 2 3 4 cot 2 cot 2 tan 2 45 ect Answer 1 Sunattempted dd to Bookmark List 17 For the hollow thin cylindrical current carrying pipe which statement is co Right Answer 31 Your Answer Difficulty tovallow Topic physics magnetic affect of current and magnetism Poor Stat x Unattempted 281 Correct 20 7 Incorract 531 A dip circle shows on apparent dip of 45 at a place where the tradin 0 4

Find the value of magnetic induction at the proton due to electron motion if the radius of the first orbit hydrogen atom is 0 5 A and the speed of electron in it is 2 2 x 106 m sec

A short magnet is undergoing simple harmonic motion of time period 2 second Now the magnet is broken in four equal parts in transverse manner If one of the smaller parts is made to oscillate in similar situation then its time period of oscillation will be 1 0 5 second 3 2 second 2 1 second 4 8 second

1 Find the magnetic field at P due to the arrangement shown 2 oi b 2 n d Hoi 2 n d Hoi c 2 d 1 2 Hoi 2 nd 1 1 28 90 45 d P Joon of the edge a made of a uniform wire A current i enters the loop at the the perpendicular

9b A wire 50 0 cm long carries a 0 500 A current in the positive direction of an x axis through a magnetic field B 3 00mT 10 0mT In unit vector notation what is the magnetic force on the wire

2018015400210892 NOTE SCREENSHOT PROHIBITED ID 2018015400210892 Cr O3 A B is the example of anti ferromagnetic material O C ID 2018015400210892 Fe3O4 ID 2018015400210892 Fe 0

A thin bar magnet of length 2L and magnetic moment M is bent at the mid point so that the angle between the two halves is 60 The new magnetic moment of the bar magnet will be MIN OM 2 2M 8M O 4M

The role of quick lime in soda lime mixture is to a absorb moisture present in soda lime b increase the efficiency of soda lime c absorb carbon dioxide present in soda lime d take part in reaction with NaOH

A non conducting rod AB of length has total charge Q The rod is rotated about an axis passing through a point distance from one 3 end and perpendicular to plane of rod with constant angular speed oo the magnetic moment of rod is 1 Ql w 12 2 Ql w 18

A 1 mm thick iron sheet is placed on top of a bar magnet Iron filings are placed on the iron sheet jus above the bar magnet The set up is turned upside down while holding the sheet firmly The magnet now on top and the sheet below it The procedure is repeated using a glass and a cardboard sheet the same thickness as the iron sheet On which of the upturned sheets are iron filings likely to be seen sticking B C only on the iron sheet only on the cardboard sheet only on the glass and cardboard sheets on all three sheets iron glass and cardboard

Two magnets of magnetic moments M and 3M are joined to form a cross The combination is suspended freely in a uniform magnetic field In stable equilibrium position the angle between magnetic moment M and the field is 1 30 2 45 3 60 4 90

1 2Q 2Q 3 Q 3Q A particle of mass m and charge q circulates around a fixed charge q in a circle of radius r under electrostatic force The total energy of the system is 1 3 k 2 Q 3Q 4 2Q 3Q 1 4 0 kq 2r kq 2 kq r 4 Zero 2 Potential of the 3 Potential a charges is 4 Both 2 16 When a die placed insi electric fie 1 E

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

33 36 The area of hysteresis loop of a material is equivalent to 250 Joule m When 10 kg material is magnetised by an alternating field of 50Hz then energy lost in one hour will be if the density of material is 7 5 gm cm 1 6 x 104 Joule 3 3 x 102 Joule 2 6 x 104 Erg 4 3 x 102 Erg

TW H R masses 5 kg and 3 kg connected twa rope of mass 2 kg are resting on a frictionless Her as shown in the following figure If a constant fores of 100 N is applied to 5 kg block then the tension in the rope at points A B and Care respectively given by 13 kg CBA 5 kg 100 N 60 1 15 N 20 N 25 N 2 25 N 20 N 15 N

Q 130 A spherical shell of radius r carries a uniformly distributed surface charge q on it A hemispherical shell of radius R r is placed covering it with its centre coinciding with that of the sphere of radius r The hemisphere has a uniform surface charge Q on it The charge distribution on the sphere and the hemisphere is not affected due to each other Calculate the force that the sphere will exert on the hemisphere Spus Yoo Re x X X x O R C r 9

Charge q is uniformly distributed over the surface of an annular non conducting disc of inner radius R and outer radius R The disc is made to rotate about an axis passing through its centre and perpendicular to its plane with a constant frequency v rotations per second Magnetic moment of the disc can be expressed as Options 1 2 quv R3 R 2 qTv R R 2 qTVR

A thin rod of total length I and of mass m has variable linear density given by p P 1 x l where x is the dist from one end Calculate the moment of inertia in kg m about an axis perpendicular to the length of the rod a passing midway at x 1 2 Take p 1 kg m 1 2m

Particle of charge e is moving with an initial velocity when it enters midway between two plates where there exists a uniform magnetic field pointing into the page as shown figure You may ignore effects of the gravitational force The magnitude of the velocity of the particle if it just strikes the end of the plate O eB d m 2 d eB 12 d 0 XXXXXXX X XX

Copper is diamagnetic with susceptibility 9 7 x 10e 6 Its electric and static magnetic properties depend on its atom having a single outer electron 4s The textbook presents a model for diamagnetism Chap 6 1 3 Assuming one Cu atom is essentially a single electron in a circular orbit around a positive core what radius would the electron orbit need to account for its susceptibility

The inductive reactance of an AC circuit is 11 2 Find the rms current of the circuit if the inductance of the inductor is 34 H and the rms voltage of the circuit is 48 V A 0 36 A B 2 22 A C 3 35 A D 4 36 A Answer ABU C

2 When bar magnet is made to vibrate in horizontal plane the time preiod of vibration is 3 2s Angle of dip is 60 Find time of vibration when it vibrates in vertical plane parallel to the magnetic meridian at the same place 1 3s 3 1 3 sec 2 4s 4 3 s

A fixed cylindrical tank having large cross section area is filled with two liquids of densities p and 2p and in equal volumes as shown in the figure A small hole of area of cross section a 6cm is made at height h 2 from the bottom Area of cross section of stream of liquid just before it hits the ground h A 2cm C 1cm 2p area 6 cm h 2 R B 3cm D 5cm

bt Problem 5 A wire of cross sectional area 4 x 10 m modulus of elasticity 2x 10 Nm and length 1 m is stretched between two vertical rigid poles A mass of 1 kg is suspended at its middle Calculate the angle it makes with horizontal Solution Follow solved Problem 4 sin 0 0 Mg YA 71 3

Q 18 Ordinary magnetic needle magnetic needle moving in a horizontal plane can be use to determine at a place on earth s surface a magnetic declination b magnetic inclination c both a and b d none of these

A solution containing 30 g of a non volatile solute exactly in 90 g water has a vapour pressure of 2 kPa at a given temperature When 18 g of water is added to the solution the new vapour pressure becomes 2 9 kPa at the same temperature the molar mass of the solute is Only One Correct Answer A B C D 34 g mol 1 24 g mol 1 46 g mol 1 17 g mol 1

A telephone cable at a place has four long straight horizontal wires carrying a current of 1 0 Ain the same direction east to west The earth s magnetic field at the place is 0 39 G and the angle of dip is 35 The magnetic declination is nearly zero What is the resultant magnetic field at a point 4 0 cm below the cable

Q 13 A single layer conducting coil is wound on a cylindrical frame of radius R such that there are no gaps between the turns Diameter of cross section of the wire is d R If breaking strength of material of the wire is Sm at what magnitude of current will the coil break