Magnetic Field Questions and Answers

1 A proton and an a particle having equal kinetic energy are projected in a uniform transverse electric field as shown in figure nothies 1 Proton trajectory is more curved 2 a particle trajectory is more curved 3 Both trajectories are equally curved but in opposite direction 4 Both trajectories are equally curved and in same

A vibration magnetometer consists of two identical bar magnets placed one over the other such that they are mutually perpendicular and bisect each other The time period of oscillation in a horizontal magnetic field is 4 sec If one of the magnets is taken away find the period of oscillation of the other in the same field in sec

5 Four wires each of length 10 m are bent loops A B C and D and then suspended into uniform magnetic field such that field lines are parallel to the plane of loop Same current is passed through each loop then in which loop couple will be maximum MAX 221 10 A B yat so A 3 C 180 C D 2 B 4 D T MB the barrier potential

A coil with inductance L and resistance R is connected to an alternating source The capacity of a capacitor connected in series with the coil such that active power of circuit does not change is given by C 1 no L value of n Find

In a bar magnet angle between the magnetic axis and magnetic moment is choose the best possible answer 0 60 90

A current carrying long solenoid is placed on the ground with its axis vertical A proton is falling along the axis of the solenoid with a velocity v When the proton enters into the solenoid it will 1 Be deflected from its path 2 Be accelerated along the same path 3 Be decelerated along the same path 4 Move along the same path with no change in velocity

18 2 Amp Ring 12 1 Amp Two co axial rings of same radius R 10 cm are placed parallel to the y z plane such that x axis is the axis of the rings Ring 1 carries a current of 2 Amp and ring 2 carries a current of 1 Amp as shown in the figure The separ ation between the rings is d B dx 50 cm Find the magnitude of where B is the net HO magnetic field due to both the rings a t any point on the x axis Ste Ring 2 d 50 cm 4 C 2 O H ZA P

Q 1 The smallest division on the main scale of a Vernier calipers is 0 1 cm Ten divisions of the Vernier scale correspond to nine divisions of the main scale The figure below on the left shows the reading of this calipers with no gap between its two jaws The figure on the right shows the reading with a solid sphere held between the jaws The correct diameter of the sphere is C 3 15 cm B 3 11 cm D 3 17 cm 0 main scale Vernier scale 10 1 3 main scale

26 A potentiometer wire is 10m long and a potential difference of 6V is maintained between its ends The emf of a cell which balances against a length of 180 cm of the potentiometer wire 1 1 8 V 2 1 1 V 3 1 08 V 4 1 2 V

Two wires A and C carry equal current 1 A as shown in figure One end of both wires extends to infinity If magnitude of magnetic induction at point Pon the angle bisector of AOC at a distance 1 cm from point O is K x 10 5 tesla then find value of K k P 0 37 0 C Answer D0 01 02 0 3 04 05 06 07 08 09

1 A proton and an alpha particle are separately projected in a region where a uniform magnetic field exists The initial velocities are perpendicular to the direction of magnetic field If both the particles move along circles of equal radii the ratio of momentum of proton to alpha particle is 1 1 3 2 2 1 2 4 1 4 P P P NCO

An a particle is describing a circle of radius 1 m in a field of magnetic induction 2 T The potential difference required to accelerate the particle The mass of a particle is 6 8 x 10 27 kg and its charge is 3 2 x 10 1 coulomb will be O 6 x 106 V 9 4 107 V 0 7 106 V 3 2 10 12 V

The effective radius of a coil of 100 tur ns is 0 05 m and a current of 0 1 amp is flowing in it The work required to turn t his coil in an external magnetic field of 1 5 T through 180 degree will be if initi ally the plane of the coil is normal to th e magnetic field

Which of the following statement is not true magnetic field at the centre of current carrying loop 1 proportional to current 2 inversely proportional to radius 3 proportional to number of turns 4 none

13 A closely wound flat circular coil of 25 turns of wire has diameter of 10 cm and carries a current of 4 ampere Determine the magnetic flux density at the centre of the coil 1 1 679 x 10 5 T 3 1 257 10 T 2 2 028 x 10 4 T 4 1 512 x 10 6 T

SolveLancer Test The length of a solenoid is 0 8m It has 4500 turns and 15 A current is flowing in it What will be the value of energy density of the magnetic field stored in solenoid Given radius of solenoid is 9 cm SolveLancer Test a 4 474 10 b 2 474 x 10 m c 3 323 x 10 d 2 474 x 10

IS A charge q is V 14 m s at a point in a magnetic field and experiences a force q 13 1k N If the charge s a moving with V2 that point is 1 m s at the same point it experiences and a force A k Wb m B 1 k Wb m C 1 1 k Wb m Roqu IIN T DY EM velocity magnetic induction Ba learn from the Best ET I Foundation

0 Figure shows a square loop with edge length a meter The resistance of wire ABC is T Q and that of ADC is 3r 2 Magnetic field at the centre of the loop is 1 3 20A A B 10 20 t 2H0 8 D 2 4 10 2 0 2 0 n O 30 a fick you and yes nicht aufaa ya ABC ADC 3r 3 20A A 10 20 2 O B D 2 4 10 2 0 n 2 0

Two long straight wires of telephone circuit inside a house are coplanar with and run parallel to a third long straight conductor that carries a current i i sinot The conductor induced a noise in the telephone circuit The rms voltage per unit length of this 2 2 A 50rad s In 2 induced noice is xx5 find x Express your answer in V Take d 2d i Id d I sin cot

A uniform ring of mass m with uniformly distributed charge q along its circumference of radius K is translating with speed vo perpendicular to a uniform magnetic field as shown The acceleration of the ring is Assuming gravity free space B A 2qvoB m C 0 B CUTT Vo D m

An electron is moving on a circular orbit of radius r with speed v It produces a magnetic field B at its centre then radius of circle is proportional to 1 3 B N 2 4 V B 0

An electron is moving along positive X axis A uniform electric field exists towards negative Y axis What should be the direction of magnetic field of suitable magnitude so that net force on electron is zero 1 Positive Z axis 2 Negative Z axis 3 Positive Y axis 4 Negative Y axis A

A volumetric charge density of value p pnC m exists in a long cylindrical shell with an inner radius p 1 0 cm and outer radius po 2 0 cm Find a the electric flux density vector everywhere in space 0 p b the electric field strength everywhere in space 0 ps c the potential difference between two points at distances of 0 5 cm and 2 5 cm from the z axis d the potential energy stored in one meter of this system of charges Transmission line and electromagnetics course Please solve this question in detail thank you

9 A square coil of side 10 cm consists of 20 turns and carries a current of 12 A The coil is suspended vertically and the normal to the plane of the coil makes an angle of 30 with the direction of a uniform horizontal magnetic field of magnitude 0 80 T What is the magnitude of torque experienced by the coil

3 A closely wound solenoid 80 cm long has 5 layers of windings of 400 turns each The diameter of the solenoid is 1 8 cm If the current carried is 8 0 A estimate the magnitude of B inside the solenoid near its centre

given T What is the magnetic force on the wire Two long and parallel straight wires A and B carrying currents of 8 0 A and 5 0 A in the same direction are separated by a distance of 4 0 cm Estimate the force on a 10 cm section of wire A A olacak mound coloncid 20 windings of 400

A 3 0 cm wire carrying a current of 10 A is placed inside a solenoid perpendicular to its axis The magnetic field inside the solenoid is given to be 0 27 T What is the magnetic force on the wire

1 5 6 What is the magnitude of magnetic force per unit length on a wire carrying a current of 8 A and making an angle of 30 with the direction of a uniform magnetic field of 0 15 T A 30 cm wire carrying a current of 10 A is placed inside a solenoid

A rectangular loop of side a and b has a resistance R and lies at a distance c from an infinite straight wire carrying current To The current decreases to zero in time to I t Io to t 0 t to The charge flowing through the rectangular loop is b IH a dx IX C Io

charges Q 2Q respectively as shown Find heat loss in the resistance R after the switch is closed A B C 9 20 Only One Correct Answer 20 8 0 C 2Q 30 F 2C wwwww R www 2R i

d P d 9 Consider the figure above Take d 4 40 m g 1 40 x 10 C and v v 50 0 m s a Determine q if the net magnetic field at P is zero C b Determine the magnitude of the the net magnetic field at P if q 2q T c Determine the direction of the net magnetic field at P if q 2q Upward Downward O Rightward O Leftward O Into the page Out of the page O None of the above

with the 3 2 it makes angle 0 tan vertical field with the 2 When it makes angle 0 tan vertical field with the 9 3 When it makes angle 0 tan horizontal field with the 9 4 When it makes angle 0 tan horizontal field 11 A bar magnet of magnetic moment M is hung by a thin cotton thread in a uniform magnetic field B Work done by the external agent to rotate the b magnet from stable equilibrium position to with the direction of magnetic field is change in angular speed is zero NCER eometrical length of a bar magnet is less en magnetic length gnetic field lines inside a bar magnet is from th pole to north pole e strength is a scalar quantity tain place a freely suspended magnet 0 oscillation per minute At another place e magnetic field is double its time period NCERT Pg 178 4 tan MB magnetic susceptibility of a paramagnetic at 23 C is 0 0015 Then its value 2 3MB 2 tan 8 tan 6 tan tan 5 M 4 12 At a place apparent d of dip circle is at an meridian The tr 3 MB etic meridian 30 then H M 2 13 3 10 A bar magnet of magnetic moment M is gently placed inside the two mutually perpendicular magnetic field By 6T and B 2T as shown in figure The net torque on the bar magnet will be NCERT Pg 178 zero B

5 A dip circle is taken to magnetic equator Th needle is allowed to move in magnetic meridian the needle will stay 1 In horizontal direction 2 In vertical direction 3 In any direction it is released 4 In any direction except vertical or horizontal

Q 30 Currents of 10 A and 2 A are flowing in opposite directions through two parallel wires A and B respectively If the wire A is infinitely large and wire B is 2 m long then force on wire B which is situated at 10 cm from A is a 8 x 105 N 5 5 b 6 x 105 N c 4 x 105 N 5 d 2 x 10 5N

B A conducting square loop of side a is kept on a sufficiently rough horizontal surface and connected to a charged capacitor as shown in the figure The arms AB BE FC CD and DA are rigid but connecting wires EG FH can behave as strings so that the whole loop can rotate about BC The mass of each arm is m and the gap between points E and F can be neglected A uniform 5km g is the amount magnetic field is present in the x direction Upon closing the switch 3B a charge flown in circuit so as to rotate the loop by 90 about BC then find the value of k negle the resistance of wires X E C F G H q g

An insulating uniformly charged cylindrical shell of radius a lies with its axis along the z axis The shell s moment of inertia per unit length about the z axis and the surface charge density are I and a respectively The cylinder is placed in an external uniform magnetic field Bex z and is initially at rest Starting at t 0 the external magnetic field is slowly reduced to zero What is the final angular velocity w of the cylinder 0 2a Bex 2

The ratio of moment of inertia about the tanger xx axis of full ring of mass m and half ring of mas m is thickness of wire is small and wire is c same material in both cases 1 3 3 4 RAPX 3 3 4 3 8 m X X 2 4 X 3 3 4 3 4 3 4

A long current carrying wire W is free to move wher placed in a magnetic field B at right angles to the field a shown a it will move along the magnetic field to the right b it will move upwards towards you c it will move downwards away from you d it will not move at all W I B

e current flows om A to B in a straight wire as shown in figure and it is decreasing th time The induced current in loop placed near to it A In clockwise direction B In anticlockwise direction

A solenoid of radius r is made of thin metallic wire rings with resistance of each ring R The ring have been put in a uniform way on a very long glass cylinder which has vacuum inside it Th solenoid and glass cylinder are glued to each other The number of rings per unit length is n an the planes containing the rings are perpendicular to the symmetry axis of the cylinder At moment the cylinder starts rotating around its symmetry axis with an angular acceleration a Th magnetic field B at the centre of the cylinder after a long time is is specific charge m electron A B nmr a eR nmr eR

A positive charge particle enters inside a uniform magnetic field B 2 tesla as shown Time after which it will come out of this magnetic field will be 9 Given 2 S I unit m 60

The depth in water at which the total pressure is 2 atmospheres is Given density of mercury is 13 6 gr cc and atmospheric pressure is 75 cm of mercury A 980 cm B 1000 cm C 1020 cm D 1060 cm

5 69 The magnetic field in a certain region is given by B 4 0 1 8k 10 T How much flux passes through a loop of area 5 0cm in this region if the loop lies flat on the x y en plane It Ans 9 0 x 10 7 Wb Sol S 5x104 k m cal ne of BS 9 10 7 Wb

7 A 20 cm long soil column with a cross sectional area of 100 cm is used for a solute transpo study Prior to adding two solutes steady state unsaturated water flow at h 20 cm was established by adjusting the hanging water tables on the ends of the column see diagram below The solutes CI with Kp 0 and picloram with Kp 0 35 cm g are added as a narrow pulse an their breakthrough at the lower soil boundary is monitored Your objective here is to predict th average breakthrough time of each chemical through the soil portion of the system The following data may aid you in your calculations Mass of oven dry soil in column 2900 g Mass of soil at steady state water content 3600 g Hydraulic conductivity function K h Ks exp ah Ks 100 cm d 0 10 cm loam h 20 cm 20 cm h 20 cm

6 0 5 points A magnetostructural system has a cubic magnetocrystalline anisotropy constant K 0 When the system undergoes a phase transition towards a tetragonal phase the easy magnetization axis becomes the short axis This means that the ferroelastic phase with the ferroelastic variant e 0 will favor a magnetization m my my with a my mx M b mx c mx 0 my 0 d mx 0 my 0

A very long solenoid is to be constructed by tightly wrapped wire with a magnetic field of 0 168 T at its centre The radius of solenoid is to be 0 01 m and the wire carries a current of 2 A If the solenoid is 1 4 m long what is the length of wire needed in nearest integer in m 1 4220 2 5842 3 2550 4 5880

Q 7 A particle of mass m and charge q is projected along the radial direction towards a solenoid of radius R turns per unit length n carrying current i If the speed of projection of particle is v determine the time it spends in the solenoid

5 3 The total charge flown through a conducting loop in a given time duration when it is moved in magnetic field depend on A The rate of change of magnetic flux B Initial magnetic flux only C The total change in magnetic flux D Final magnetic flux only

The length of a thin wire required to manufacture a solenoid of length 100 cm and inductance L 1 mH if the solenoid s cross sectional diameter is considerably less than its length is 1 1 km 3 0 010 km 2 0 10 km 4 10 km

A rectangular loop of wire of length a 8 cm and width 6 3 cm carries the current I 113 A This loop lies on the zy plane Find the magnitude of the magnetic field 4 cm above from its center in units of microtesla T Take 44m x 10 T m A and 3 14