Magnetic Field Questions and Answers

A charge particle having charge qis projected with velocity Vo in the plane of current carrying loop ABCD as shown Magnetic force on charge particle is b 0 qVotole b a 2 ab q Vottole ab qVotole 5 ab b a b a q Vottole b a a

in the figure shown two loops ABCD EFGH are in the same plane The smaller loop carries time varying current I bt where b is a positive constant and t is time The resistance of the smaller loop is Y and that of the larger loop is R Nes the self inductance of large loop The magnetic force on the loop EFGH due to loop ABCD is lab Mn3 X R Find out value of x D B C E H a F G b a

B ds 0 equation is not according to the following 3 B ds 0 35606 500 000 5 Options The net magnetic flux enclosed by any closed surface is zero Josje dood boas s o sor n tr p n No isolated magnetic poles are available De er odos The magnetic flux is positive at some place and it is negative at some other place as dos anys to resor o s Hoevo8 The number of magnetic lines leaving a surface is not equal to that of entering the surface 25 500 500 2006 go outyou wodper doo 5308 5 wodne Songs Sar o 50

An electron moving in a uniform magnetic field 41 6j nk T experiences a force 21 3j 4k N Then the value of n is 41 6j nk T Ke D ia wodiyos dos K k nst no Jog p no n 21 3j 4k N so n Deus Options 2 5 1 2 6 5 3 4 5

a b 1 along x axis 3 along z axis X A semi circular current carrying loop is placed near an infinite straight wire with its section ab parallel to the wire as shown The net magnetic force on the loop is 2 along y axis 4 zero

A current carrying long wire and the rod PQ are in same plane The rod moves parallel to the wire with a velocity v as shown Which of the following is correct about nduced emf in the rod O End P will be at lower potential with respected to Q OP and Q will be at same potential O There will be no induced emf in the rod O Potential at P will be higher than at Q 31 36 41 46 51 56 61 42 47 52 57 62 58 63 54 59 64

A dip circle is taken to magnetic equator The needle is allowed to move in magnetic meridian the needle will stay In horizontal direction In vertical direction In any direction it is released how Come In any direction except vertical or horizontal If 2ph

onducting rod OA of length 2 I is rotated about its end O with an angular velocity in a uniform magnetic field B directed perpendicular to the plane of rotation The ential difference across its two ends is Bool2 2Bol 21 26 31 36 41 46 51 22 27 32 37 42 47 52 23 28 33 38 43 48 53 24 29 34 39 44 49 54

wi arge q is endicular of the field ge particle 102 force 1 A positive charge projected past a piece iron 2 A positive charge sent along the axis of a solenoid e and a mean of 0 3 A 3 Two parallel wires carrying current in the same direction 4 A positive charge projected between the poles of a magnet 103 A straight wire of length metre is carrying a current of 2 A and the magnetic field due to it is measured at a point distance 1 cm from it If the wire is to be bent into a circle and is to carry the same current as before the ratio of the magnetic field at its centre to that obtained in the first case would be 1 1 100 8 1 50 2 100 1 4 50 1 104 Magnetic dipole moment is a 1 Scalar quantity Vector quantity for all magnets ont quantity 7623456

3 A current element of strength 2x 10 Am placed at the corner A of a square ABCD of side 10 cm Magnetic field induction at the point which is at diagonally opposite corner of the square due to the element is The element lies along the side AB 1 0 7 x 10 9 Wb m 2 1 2 x 10 9 Wb m 3 2x 10 9 Wb m 4 Zero oving in a circular orbit of rac

questions place e g 06 25 07 00 00 33 00 30 30 27 27 30 If flux through a loop is given by 21 Wb then induced emf in the loop at r 2 s will be n volts Find the value of n Answer Port to the second dec 21 26 31 22 27

Which of the following is incorrect about Lenz s law It explains the physical significance of the negative sign in faraday s law O It is a consequence of conservation of energy O It tells about the transformation of mechanical energy into electrical energy O Lenz s law explains the force acting on current carrying element 21 26 2 31 E E 36

gure shows two concentric loops of radii r and r2 Mutual inductance of the arrangement is OM Ho 2r O ME 2x 25 OM Ho 21 OM H 4r 16 21 26 31 36 41 46 51 56 61 17 22 27 32 37 42 52 57 62

62 Moving An electron and a proton are revolving around common centre O in two coplanar circular paths as 2 s respectively The net magnetic field at O will be shown in figure with time period of rotation 1 s and Je 228 1 Hoe I tesla tesla e Tim 12m Hoe 2 2 4 Zero tesla

2 Only outside 3 Both inside and outside the rod 4 Neither inside nor outside the rod The magnetic intensity near one end of a long solenoid of length L and having N turns and carrying current i is given as 1 H Ni Ni 3 24 2L 2 MoNi 2L 4 HoNi ensional formula of magnetic inte 2 MOL 1TO

3 A To compensate the relativistic variation of mass at high speed of charge in cyclotron Adjustments can be made is 1 Frequency of a c is decreased 2 Magnetic field is increased 3 Peak value of a c is increased 4 Both 1 2 f length is folded to form double circula wire is i the magnetic fie

Use phasor addition to find the resultant amplitude and phase constant when the following three harmonic functions are combined E sin wt 6 E 3 0 sin wt 77 2 and E3 6 0 sin wt 4 3

A particle of charge 1 C moving with velocity V 21 31 m s experiences a constant force F 121 81 N due to a constant magnetic field in z direction of strength x Tesla Find the value of x

A uniform wire of mass 3m and length 31 is bent into the shape of an equilateral triangle and suspended from a horizontal axis X X in a vertical plane as shown A uniform vertical upward magnetic field B is existing in the region If charge Q is passed almost instantaneously through the triangular loop then the angular velocity acquired by the triangular loop immediately after charge passed is A C 3BQ 5m 3 3BQ 5m B D 2 3BQ 5m 4 3BQ 5m B B m B m m

A charged particle q of mass m is placed at a distance d from another charged particle 2q of mass 2m in a uniform magnetic field B as shown in figure If the particle are projected towards each other with equal speed of 2Vm where Vm is the maximum value for which the two particles do not collide then the time after which collision occurs between the particles is found to be nm where value of n is qB q m 2Vm 2Vm d 2q 2m

An amplitude modulated signal is given by V t 10 1 0 3 cos 2 2 x 1041 sin 5 5 x 105t Here t is in seconds The sideband frequencies in kHz are Given n 22 7 1 1785 and 1715 2 178 5 and 171 5 3 89 25 and 85 75 4 892 5 and 857 5

conducting rod of length 5 m slides in a vertical plane against two insulated perpendicular surfaces s shown Outward uniform magnetic field B 3 tesla exists in the region If end A of the rod is being ulled with constant speed V 2 m s 7 then find the magnitude of induced Emf in volt across end A nd B of the rod at the instant when the rod makes an angle of 0 37 with horizontal B 3 T B 1 37 A 2 m s I

From the following displacement time graph find out the velocity of a moving body Time sec 30 Displacement meter Question Type Single Correct Type 1 3 m s 2 3 m s 3 3 m s

ple 23 A current carrying circular loop of radius R is placed in a uniform magnetic field B Tesla in x y plane as shown in figure The loop carries a current i 1 A in the direction shown Find the torque acting on the loop V ANS on V M TR K T B B cos 45 i B sin 45 j t MxB VED BY R kx i j 2 AIDUAL CAMERA TR B i 1 2 makanya kalau 45 V crock wise ve sign 2021 08 21 15 38

0 375 x 18 x 10 6 75 X mple 9 A magnetic dipole of magnetic moment M is placed on the axis of a current carrying circular la of radius R at a distance x from the centre Find the force acting on the dipole

For each question enter the correct numerical value in decimal notation truncated rou Answer to each question will be evaluated according to the following marking scheme Full Marks 4 If ONLY the correct numerical value is entered as answer Zero Marks 0 In all other cases A charged particle having charge q experience a force F q 1 2k N in a magnetic field B when it has velocity 11 m s The force becomes F2 q 1 2k N when the velocity is changed to 11 m s Find the magnitude magnetic field at this point

A charged particle enters a uniform magnetic field initially travelling perpendicular to the field lines and is bent in a circular arc of radius R If the particle had the same charge but double the mass and were travelling twice as fast the radius of its circular arc would be A 2R B 4R C R D R A B O C O D

Consider a perfectly conducting disc of radius r in a constar magnetic field B perpendicular to the plane of the disk slidin contacts are provided at the edge of the disc C and its axle C After long time angular velocity will become constant and become equal to current in resistance is i then A A I D Po R ww 11 C B Bor R Bor 2R M 4MgR B r3 2MgR B r3

The ratio of magnetic moment of an electron to its angular momentum in an atomic orbit will be 2m e 2m 2 E El E

A rigid rectangular mesh measuring 0 300 m by 0 400 m carries a current of 3 70 A as shown A uniform external magnetic field of magnitude 1 20 T occurs in the negative x direction Segment CD is in the x z plane and makes an angle of 32 with the z axis as shown The external field magnetic flux through the mesh corresponds to a 0 110 Wb b 0 0920 Wb c 0 150 Wb d 0 120 Wb e 0 0760 Wb 3 7 AT 0 30 m B 32 Y KZ 0 40 m B 1 2T

QUESTION NO 7 INSTRUCTION Question given below has four answer options out of which ONLY ONE is correct Choose the area For CORRECT answer you will be awarded 4 Marks and for WRONG answer there is a negative marking question unattempted In the given figure possible direction of magnetic field for which net force on charge particle is zero q m V 1 along ve z axis 2 along ve z axis 3 along ve y axis 4 along ve y axis

SolveLancer Test A coil of 350 turns having cross section area 1 4 m The coil is placed in a region where magnetic field changes from 0 50 Wb m to 0 98 Wb m uniformly in 0 08 seconds The induced emf is applied in a wire of 200 ohm The value of heat produced in the wire in 10 seconds is SolveLancer Test a 56 02 x 10 J b 21 98 x 10 J c 4 32 x 105 J d 6 88 x 105 J a b

netic susceptibility of a 2 0 75 3 1 67 angent galvanometer is netic moment M is found y twice that of magnet B and same moment of vibration magnetometer 8 1 Depends on strength of magnetising field 2 Depends on the external condition such as temperature 3 Cannot be done beyond the saturation point 4 All of these A Gaussian surface is drawn enclosing N pole of a bar magnet The net magnetic flux through the Gaussian surface will be pole strength of N pole is treated as positive and S pole as negative 1 Positive N S Gaussian surface 2 Negative perpendic 3 Less and less vertically downwa horizontal at magnetic pole 4 Less and less vertically up horizontal at magnetic pole Soft iron is used to manufa because 1 It has high permeabili 2 Its retentivity and co 3 Its retentivity and 4 Both 1 2 A long solenoid h iron core of u flows in the c beyond curie Positive or negative 4 Zero A material when heated suddenly changes ir property at a particular temperature and its susceptibility is found hure the absolute 1 The Ha zero 2 The unch 3 TE

3 May increase or decrease in size 4 Have no relation with the field A paramagnetic material is kept in a magnetic field The field is increased till the magnetisation become constant If the temperature is now decreased the magnetisation 1 Will increase 2 Decrease 3 Remain constail 4 May increase or decrease Which of the following four graphs may best represent the current deflection relation in a tangent galvanometer 19 1 3 36 sec 3 9 sec A magnet ma place where intensity is 0 made per se place where of the field i 1 0 157 H 3 0 314H manne

a d c c Ca 4 d Ho 2 2 M 4t d EN Which of the four graphs may best represent the current deflection relation in a tangent galvanometer 2 971 b o 2 M 4 T d 40 d Ho 2M 4 d b a b a d b i 11 4 In a permanent magnet at room temperature a magnetic moment of each molecule is zero of the a If th b If c d e A 2

ng the on of eld in force A particle of specific charge kg is projecte from origin towards positive x axis with a veloci of 10m s in a uniform magnetic field B 2k1 The velocity of particle after 0 167 sec will be 1 5 5 31 m s 2 10 m s 3 5 31 5 m s 4 10 m s An infinitely long straight conductor AB is fixed and a current is passed through it Another movab straight wire CD of finite length and carrying curre Neglectin 1 6 3 4 3 3 3 4 14 A flexible conducting loop an field of strength B normal to A current I exists in the developed in the wire at equ 1 21 281 0 0

A parallel plate capacitor of area 60 cm and separation 3 mm is charged initially to 90 C If the medium between the plates gets slightly conducting and the plate loses the charge initially at the rate of 2 5 10 C s then what is the magnetic field between the plates B 2 0x10 T 2013 A 2 5 10 T C 1 63x10 1 T L D zero

34 Two long and parallel straight wires A and B carrying currents of 4A and 2A in the same direction are separated by a distance of 2 cm The force on a 10 cm section of wire A is 1 8 10 5 N 3 8 x 10 6 N 2 8 10 N X 4 8 108 N

moment u is rotated to the direction of done is sine cos0 toward earth e deflected 49 4 tan 14 3 Magnetic moment of a bar magnet shown in figure i is M S N S N 55 Fig 1 Fig ii If a hole is drilled through the magnet as shown in figure ii then new magnetic moment of the magnet will be 1 Equal to M 2 Less than M TAS Zem 3 B A com hc zo will 1 2 56

In cosmic shower an electron is falling toward earth near equator In which direction will it be deflected 1 Eastward 2 Westward 3 Northward 4 Southward in maximum for

A small conducting circular loop is placed inside a long solenoid carrying a current The plane of the loop contains the axis of the solenoid If the current in the solenoid is varied the current induced in the loop is a clockwise b anti clockwise c zero d clockwise or anti clockwise depending on whether the or decrea

Ask an Expert What is the moment of inertia of a magnet in the topic of dipole in uniform magnetic field Where is the axis for the magnet in this topic Then what is the formula for the moment of inertia of a magnet Jul 27 2021 12 15 49 PM Answer PFA IN S Answered MXB ms sino ton magnet 1 At equilibriure Id 0 MB and de 2 indicata

In the Figure shown a closed loop carries a current I 600 mA The loop consists of two radial straight wires and two concentric circular arcs of radii 2 00 m and 5 00 m The angle is T 5 The magnitude and direction of the net magnetic field at the center of curvature P is a 3 93 x 10 9 T into the page b 6 98 x 10 T into the page c 1 13 x 10 8 T into the page d 6 48 x 10 7 T into the page

3 A disc of radius R has a light pole fixed perpen dicular to the disc at the circumference which in turn has a pendulum of length R attached to its other end as shown in figure The disc is rotated with a constant angular velocity w The string is making an angle 30 with the rod Then the angular velocity w of disc is A 3g R 1 2 1 2 R B R 30 3g 2R 1 2 2g 2

Find flux through a circular disc of radius R kept in a region of magnetic field perpendicular to the disc The magnitude of field at a distance r from centre of the disc is given by B ar where a is a constant 2 R 4 TOR 3 O aR 3

4 Red light Microwaves X Ray Rad A square coil ABCD lying in x y plane with its centre at origin A long straight wire passing through origin carries a current i 2t in negative z direction The induced current in the coil is 1 Clockwise Alternating C YA B D 2 R d 2 Anticlockwise 4 Zero I

45 A charge particle of charge q and mass m enters in a given magnetic field B and perpendicular to the magnetic field as shown in the figure It enters al an angle of 60 with the boundary surface of magnetic field and comes out at an angle of 30 with the boundary surface of the magnetic field as shown in the figure Find width d in which magnetic field exist a c 3 1 mv 4qB 3 1 mv 3aB xx x x 60 x X X B XX XX x x d X x X 30 X b X X d 3 1 mv qB 3 1 mv 0 2qB

A solenoid 1 0m long and 0 04 m diameter has 700 turns Another solenoid of 50 turns is tightly wound over the first solenoid Then the emf induced in the second solenoid when the current in the first solenoid changes from 0 to 5 A in 0 01 s Take f 10 is nx10 volts Find n ignore edge effects

Three long wires carrying current 10 A 20 A and 30 A are placed parallel to each other as shown Point P and Q are in midway of wires What is ratio of magnetic field at P to the Q 30 A 1 02 1 03 2 02 3 2d 20 A 2d P 10 A

S a 6 23 A particle having charge q enters a region of uniform magnetic field B directed inwards and is deflected as shown The magnitude of the momentum of the particle is qBy 2 qBy 2 a 0 2 X X y b 9By X d 9By2 2x BA