Magnetic Field due to current Questions and Answers

A point charge q is rotating in a circle of radius R with angular frequency o The magnetic field created by it at the centre of the circle will be 1 Haw 2 R 2 qw 4TR

2 A metallic rod of mass per unit length 0 5 kg m is lying horizontally on a smooth inclined plane which makes an angle of 30 with the horizontal The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction 0 25 T is acting on it in the vertical direction The current flowing in the rod to keep it stationary is 2018 a 14 76 A c 7 14 A b 5 98 A d 11 32 A

A small circular loop with radius 0 6 cm is lying parallel and coaxial to a much bigger circular loop having radius 20 cm The distance between their centers is 15 cm If a current of 4 0 A is flowing through the smaller loop then the magnetic flux linked with bigger loop has a value of O 9 1 x 10 1 weber 10 meher O 72 8 x 10 11 weber O 6 6 x 10 weber

9 A bar magnet of length e and magnetic dipole moment M is bent in the form of an arc as shown in figure The new magnetic dipole moment will be 1 M N 3 M T 60 2 M 2 4 M

The figure shows the electric field lines of three charges with charge 1 1 and 1 The Gaussian surface in the figure is a sphere containing two of the charges The total electric flux through the spherical Gaussian surface is 1 Positive 2 Negative 3 Zero 4 Impossible to determine without more information

What is the magnetic field at the point of intersection of diagonals of a current carrying square loop of each side L The current through the loop is I 1 4m L 2 44 3 No 8 21 4m L 4 None of these

In the diagram shown a non uniform magnetic field B Box k is present in the region A charged particle q m enters the region with velocity vi from origin as shown Minimum possible value of curvature of path followed by particle when it is in the magnetic field is given by Y A 2 C mvo qB mvo 2qB X XXXXX xx xxxx x xxx xxxx X X X X X xx XXXXXXX xxxx xxx q m B D mvo qB 2mv qB

Through each of two long straight parallel conducting wires kept 4 cm apart 10 A current is flowing If the direc tion of current in the wires are mutually opposite what will be the magnitude of magnetic field produced at a point just midway between the two wires 0 0002 T

11b A solenoid that is 95 0 cm long has a radius of 2 00 cm and a winding of 1200 turns it carries a current of Calculate the magnitude of the magnetic field inside the solenoid

A current of 6 A passes through the wire shown in figure Then magnitude of magnetic field at point o is T The radius of are is 0 2 m 4 4x107 TmA 6A O O O O O C O D OB O A A 1 41x10 C Zero B 1 41x10 D 1 41 10

26 A rectangular loop which was initially inside the region of uniform and time 3 independent magnetic field is pulled out with constant velocity v as shown In the figure X X X X X X x x x x X X X XXX X X X X X X X X X X X X XXX X X X X X X X a a Sketch the variation of magnetic flux the Induced current and power dissipated as Joule heat as function of time b If instead of rectangular loop circular loop is pulled out do you expect the same value of induced current Justify your answer Sketch the variation of flux in this case with time

In an n sided regular polygon the distance from centre of Paragraph 1 Q No 49 to 50 polygon to each vertex is a and the length of each side is l then answer the followings 49 What will be the Magnetic field value at the centre of polygon TT Hoi sin FF nui sin n 1 1 a n 1 5 Moi sin 2 a 2 a 1 n 1 a i cloc n for

A helium neon laser beam 2 632 nm of intensity 1 0 W cm is travelling along x axis in vacuum Find a Amplitudes of E and B fields associated with the laser beam b Expression for E x t and B x t if the E field is polarized along y direction

Two wires of the same cross sectional area and electrical conductivity o and o are connected as shown in the figure If a constant current I is made to pass through the wires find the induced charge density at the junction between the two wires 8 1 4 2 2F 4

A uniform magnetic field is directed into the pago A charged particle moving in the plane of the page follows a clockwise spiral of decreasing radius as shown in the given figure Which of the following statomonts is correct 3 4 The charge is positive and slowing down The charge is nogative and slowing down The charge is positive and spooding up The charge is negative and spooding up

A uniform electric field E is present horizontally along the paper throughout region but uniform magnetic field Bo is present horizontally perpendicular to plane of paper in inward direction right to the line AB as shown A charge particle having charge q and mass m is projected vertically upward and crosses the line AB after time to The speed of projection if particle moves after to with constant velocity given qE mg is nto Find the value of n g 9 8 m s q m EG

2 A long hollow cylindrical conductor of length L and small radius carries total current along its curved surface as shown in figure The magnetic field inside the cylinder is Tesla The value of k Hol KL is

14 A charge q moving along the x axis with a velocity v is subjected to a uniform magnetic field E acting along the z axis as it crosses the origin O i Trace its trajectory ii Does the charged particle gain kinetic energy as it enters the magnetic field Justify your answer 156

X axis Find the coil for a compass n south direction ed from 0 curns It is placed A dip needle is of rotation Ans a 1A b 0 5V 4 68 A Rowland ring of mean radius 15cm has 4500 turns of wire wound on a ferromagnetic core of relative permeability 800 Find the magnitude of the magnetic field in the core for a magnetising current of 1 2A Ans 5 76T

circular coll carrying current of single turn of radius R and mass 1 kg is hanging by two ideal strings as shown in figure When a constant magnetic field B is set up in 9 he horizontal direction as shown then the ratio of tension in strings will become P 3 find value of P Given R 481 T 3 11 16 Not Answ 12 17

A uniform conducting wire ABC has a mass of 10 g A current of 2A flows through it The wire is kept in a uniform magnetic field B 2T The acceleration of the wire will be X X X X B X 4cm X X Ax X X 5cm X X X C 1 Zero 2 12 ms along y axis 3 1 2 10 ms along y axis 4 0 6 10 ms along y axis y Z O

A particle of charge 16 x 10 18C moving with velocity 10 ms 1 along the positive x axis enters a region where a magnetic field of induction B is along the positive y axis and an electric field of magnitude 104 V m is along the negative z axis If the magnetic field is switched off and the same electric field is maintained the path of the particle is Circle Parabola Straight line ellipse Th

Question NO A uniform electric field exists in a region A charged particle q m enters at point A with velocity voj It moves through the electric field and exit at point B with velocity x 7 then OE DE A a 0 E 3mv 8ga x 8ga 2 3mv 8qa mv 4ga B 2a a When the charged particle reaches at point B then a uniform magnetic field Bk is switched on now force on charged particle will be along z axis at point B 54 1 6 11 16 21 26 31 36 41 PE wa Not 2 7 12 17 22 27 32 37 42 ww

B A particle of charge q and mass m moving under the influence of uniform electric field E Eoj and uniform magnetic field Bok follows a trajectory from P to Q as shown in the figure The velocity at P is V voi Vo and velocity at Q is magnitude of electric field is given by VO 2R xxx X X X X x45 X X X X X X X X mv 890 a X O 3mv 4qa X O 7mv 8qa 5mv X X X X Vo

6 A charge particle q velocity v 51 m s passes through a region of where uniform magnetic field width D B 2k T exist as shown Find average force exerted by magnetic field on this charge particle ya 1 3 q D 5 m s 360 7 31 N 53T 360 31 N 53T 2 4 X 360 31 N 37T 360 31 N 37T

A particle of mass m and charge q moving with velocity Venters region II normal to the boundary as shown in the figure Region II has a uniform magnetic field perpendicular to the plane of the paper The length of the region II is Choose the correct choice s Region I Region II Region III XXXX X X X X X X X X X X X X X X X X The particle enters Region III only if its velocity V qIB m The particle enters Region III only if its velocity V B m Path length of the particle in Region II is maximum when velocity V qIB m Time spend in Region II is same for any velocity V as long as the particle returns to Region I

particle of mass M and positive charge Q moving with a constant velocity 4 ms enters a region of uniform static magnetic field normal to the x y plane The egion of the magnetic field extends from x 0 to x L for all values of y After passing through this region the particle emerges on the other side after 10 milliseconds with a velocity 2 31 jms The correct statement s is are The direction of the magnetic field is z direction The direction of the magnetic field is z direction 50 M 3Q The magnitude of the magnetic field is The magnitude of the magnetic field is 100 M units units

17 A rod is moving on rails as shown in figure Outside magnetic field is given by B Resistance of system is R and length is I a Find direction of induced current b Find emf and current c Find magnetic force on the rod www O Bo

A toroid has core non ferromagnetic inner radius 20 cm and outer radius 30 cm around which 3000 turns of a wire are wound If current in the wire is 10 A Then magnetic field at distance 5 cm from inner radius inside the core of the toroid will be 1 12 mT 3 6 mT 2 18 mT 4 24 mT

A uniform electric field exists in a region A charged particle q m enters at point A with velocity v It moves through the electric field and exit at point B with velocity xi 7 then 2 y U mv mv 8qa 8qa A a 0 mv 3mv 8qa 4qa X 2 B 2a a X When the charged particle reaches at point B then a uniform magnetic field B

9 The magnetic field intensity at point P in the given figure is zero The position of point P is A B 1 5 cm from wire A 3 6 cm from wire B 3 A In P 10 cm 2 A 2 4 cm from wire B 4 8 cm from wire B

Consider a wire placed along z axis and having current lo along z Holo axis If Bd along the path PRQ shown in figure is then find the value of K a 2 a Answer 0 01 02 03 04 05 06 07 08 09 0 01 02 03 04 5 6 07 08 9

in a pe An infinitely long straight conductor carrying a current I produces a magnetic field B at a point distance a from it What must be the radius of a circular coil carrying the same current I so that the magnetic field i at its center is 2B and ii at an axial point distance equal to the radius is B

Two straight parallel conductors carrying equal currents in the same direction are kept at a distance d apart in vacuum What is the magnitude and direction of magnetic field midway between the two wires What change in the force will one observe when the conductors are kept in a medium of permeability u other factors remaining the same GULD

An ac generation 1 Involves rotation of a coil in a magnetic field parallel to axis of rotation of the coil 2 Involves rotation of a coil in a magnetic field perpendicular to axis of rotation of the coil 3 Works in the principle of eddy currents 4 Involves just rotation of coil and there is no need of external electric or magnetic field

A long rigid wire lies along the X axis and carries a current of 10 A in the positive X direction Round the wire the external magnetic field is B 1 2x with x in meters and B in Tesla The magnetic force in SI units on the segment of the wire between x 1 m and x 4 mis A B C 1260 1280 3 1310 D 420

A rectangular coil carrying a current I has mass m If is place in a uniform magnetic field B as shown i The minimum value of B for which the coil will rotate mg 4 Il ii The coil will rotate about the side AB iii The deflection torque is 4 BIL 1 i ii 3 ii iii B A 2 i iii 4 i ii iii 21 B

Two wires A and C carry equal current lo 1 A as shown in figure One end of both wires extends to infinity If magnitude of magnetic induction at point P on the angle bisector of AOC at a distance 1 cm from point O is K x 10 5 tesla then find value of K lo A 0 37 P C

Four parallel conductors are arranged as shown in the figure The conductors carry currents 11 12 13 and 14 respectively Calculate a the total magnetic field amplitude direction at the midpoint O b the force per unit length amplitude direction acting on conductor number 4 1 a a 2 13 OI 3 a 2 4 1 O a 13

consider a wire placed along z axis and having current along z axis If Bd along the path PRQ shown in figure is Hola then find the value of K a nswer T 0

If an electron enters a magnetic field with its velocity pointing in the same direction as the magnetic field then 1 the electron will turn towards right 2 the electron will turn towards left 47 3 the velocity of the electron will increase 4 the velocity of the electron will remain unchanged

N An a particle experiences a force of 3 84x10 14 when its moves perpendicular to magnetic field of 0 2 Wb m then speed of the a particle is 2 5 0 x 105 m sec 1 6 0 x105 m sec 3 1 2 x 106 m sec 4 3 8 x 10 m sec MG0041

3 A long solenoid having 200 turns cm and carries current i Magnetic field at its axis is 6 28 x 10 2 wb m2 An another solenoid having having 100 turns cm and carries current then magnetic field at its axis will be i 3 1 05 x 10 4 Wb m 2 1 05 x 10 2 Wb m 3 1 05 x 10 5 Wb m 4 1 05 x 10 Wb m

electric field on the surface of pipe is zero MG0025 6 In a current carrying long solenoid the field produced does not depend on 1 number of turns per unit length 2 current is solenoid 3 radius of cross section of the solenoid 4 all of the above

figure carries a current i and consists of a circular arc of radius R and central anglerad and two straight sections whose extensions intersect the centre C of the arc The magnetic field B that the current produces at C is R

A straight segment OP of length L of a circuit carrying current 1 ampere is placed along x axis Two infinitely long straight wires A and B each extending from z to are fixed at y meter to y l meter respectively Wires A and B each carry current 1 ampere along positive z axis Given that O is origin of the coordinate system The magnitude of force on segment OP is A Ho 4 the Pin 1 7 7 B 2 Pen 1 2 C 2 Pen 1 2 the T 2 T D Fen 1 2 2

illustration 2 A particle with charge q and mass m enters a magnetic field of magnitude B existing only to the right of the boundary PQ The direction of the motion of the particle is perpendicular to the direction of B Find time spent by the particle in the magnetic field Short rut soluti Pix

A conducting square loop of side L and resistance R moves in its plane with a uniform velocity v perpendicular to one of its side A magnetic induction B constant in time and space pointing perpendicular to the plane of the loop with part loop outside the field as shown in figure The induced emf is X X X X x L XX X x x Zero RvB xB X X X Read More X

the wires as shown The a distance x to the right 1 2 Six infinite long straight parallel wires are arranged to pass through vertices of a regular hexagon of side length 3 cm as shown 3 A 2A 3A 3A 2A Find the strength of magnetic field at P 2 40uT FAX SOUT 1 20 u7 11 SOUT

A long straight wire is turned into a loop of radius 10 cm see figure If a current of 8 amperes is passed through the loop then the value of the magnetic field and its direction at the centre C of the loop shall be close to AMU PMT 2009 10cm C 8 ampere a 5 0 10 5 Newton amp meter upward b 3 4 10 5 Newton amp meter upward c 1 6 10 5 Newton amp meter downward d 1 6 10 5 Newton amp meter upward