Magnetism and Matter Questions and Answers

Ratio of magnetic dipole moment to the angular momentum for hydrogen like atoms is e and m are electronic charge and mass respectively 2 1 3 0 E e 2m 4 2e m e 4m

21 38 The time period of a freely suspended magnet in uniform horizontal magnetic field By is T If this magnet of pole strength mis divided into four parts such that the length and width of each part is half that of initial one Then the time period of each part when suspended freely in same magnetic field will be 2T T 7 2 T

The true value of dip at a place is 30 The vertical plane carrying the needle is turned through 45 from the magnetic meridian The apparent value of dip is tan cot 3 tan IN 2 150 Im tan 3 2 3

A steamer would like to move in the direction making an angle of 10 south with the west The magnetic declination a that place is 17 west from the north The steamer should move in a direction of Making an angle of 83 west with the magnetic north Making an angle of 83 east with the magnetic north Making an angle of 83 west with the magnetic south Making an angle of 27 east with the magnetic south

The value of apparent angles of dip at two places measured in two mutually perpendicular planes are 30 and 45 The true angle of dip at the place is tan 4 Xcot 4 tan 2 tan 2

Identify the correct statement from the following J K CET 2008 a Cyclotron frequency is dependent on speed of the charged particle b Kinetic energy of charged particle in cyclotron does not depend on its mass I c Cyclotron frequency does not depend on speed of charged particle d Kinetic energy of charged particle in cyclotron is independent of its charge

at a place is Bo The magnitude of the earth s magnet and the angle of dip is 6 A horizontal conductor of length I lying along the magnetic north south moves eastwards with a velocity u The emf induced across the conductor is Kerala PET 2005 a Zero c Bolu aeer b Bolusin 8 d Bolu cos d 1 incide another as shown 30 ampones

A bar magnet of length 14 cm is placed in the magnetic meridian with its north pole pointing towards the geographic north pole A neutral point is obtained at a distance of 18 cm from the center of the magnet If BH 0 4 G the magnetic moment of the magnet is 1 G 104T 1 2 880 10 J T 1 3 2 880 J T 1 2 2 880 x 10 J T 1 4 28 80 J T 1

Question 16 In the figure shown a uniform conducting rod of mass m and length is suspended in vertical plane by two conducting springs of spring constant K Upper end of springs are connected to each other by capacitor of capacitance C A uniform horizontal magnetic field B perpendicular to plane of springs exists in space initially rod is in equilibrium but if rod is pulled down and released it performs SHM Assume resistance of springs and rod are negligible non conducting roof K eeeeee m

If the angle of dip at two places are 30 and 45 respectively then the ratio of horizontal component of earth s magnetic field at two places assuming magnitude of total magnetic field of earth is same will be Question Type Single Correct Type 1 3 2 21 2 3 1 3

V3 23 When plane of dip circle is rotated by 90 from magnetic meridian gradually then dip shown by it 1 Increases 2 Decreases 3 First increases then decreases 4 First decreases then increases

A cobalt rod of susceptibility 1999 is subjected to a magnetised field of 1500 Am 1 The permeability of cobalt material is 8 x 10 4 Tm A 1 6 x 10 4 Tm A 1 O 2 x 10 Tm A 7m x 10 3 T

An iron ring of cross sectional area 6 cm is wound with a wire of 100 turns and ha saw cut of 2 mm Calculate the magnetising current required to produce a flux of mWb if mean length of magnetic path is 30 cm and relative permeability of iron is 4 3 16 A 1 06 A 2 35 A

A signal et sin wt is the input to a real Linear Time Invariant system Given K and are constants the output of the system will be of the form Ke t sin vt p 1 2 3 need not be equal to a but v equal to w v need not be equal to w but equal to a equal to a and v equal to w need not be equal to a and v

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 1 2 A Quibsh 2 2 29111 3 2 2 4 4 1 god

swer there is a negative marking of 1 Mark A wire is bent in three different shapes as shown What will be the ratio of their magnetic moments if they carry equal current 1 3 11 9 4 3 Equil ateral triangle Square 2 3 4 Circle 4 14 70

30 If the time of fall of two objects are in the ratio 1 2 find the ratio of the heights from which they fall 1 1 2 2 2 1 3 1 4 4 4 1 An obiect is dropped from a balloon rising up with a velocity 2 ms Find the velocity of the obiect after 2 seco 31

answer you be awarded 4 Marks and for WRONG answer there is a negative marking of Mark No n In the surrounding region of a small bar magnet as shown in figure the ratio of magnetic fields at P Q and R will be 1 1 1 4 2 1 2 4 3 1 8 64 R T

7 A paramagnetic sample shows intensity of magnetisation of 0 8 A m when placed in an external magnetic field of strength 0 8T at a temperature 5K When the same sample is placed in an external magnetic field of 0 4T at a temperature of 20K the magnetisation is 1 0 8 Am 1 2 0 8 Am 2 3 04 Am 1 4 0 1 Am 1

A bar magnet has coercivity 4 x 103 Am 1 It i desired to demagnetise it by inserting inside solenoid 12 cm long and having 60 turns The current that should be sent through solenoid is 1 2A 2 4A holls 3 6A 16 4 8A

Two imaginary magnetic north poles each of m amp meter are placed at the two vertices of an equilateral triangle of side a The resultant magnetic induction at the third vertex is N 1 3 Ho m Mo 4 a Mo 2 m ATT 2 a N a 2 4 a Mo 3 m 4 a Mo 4 m 4 a 2 O

field the magnetic field lines become less dense in the material iv If one limb of a narrow U tube containing a diamagneti quid is placed between the poles of an electromagnet the on switching the field the liquid shows a depression This shown in figure m N S

G If a piece of metal was thought to be magnet which one of the following observations would offer conclusive evidence It attracts a known magnet 2 It repels a known magnet 3 Neither 1 nor 2 4 It attracts a steel screw driver 8 Which of the following is correct about magnetic monopole

30 A rocket has to be launched from earth in such a way that it never returns If E is the minimum energy delivered by the rocket launcher what should be the minimum energy that the launcher should have if the same rocket is to be launched from the surface of the moon Assume that the density of the earth and the moon are equal and that the earth s volume is 64 times the volume of the moon 8 April 2019 Evening A E 4 E B E 16 E

4 52 If a magnet is suspended at an angle 30 to the magnetic meridian and in this plane the dip needle makes an angle of 60 with the horizontal The true value of dip is B tan 2 D tan 2 2 A tan 3 C tan 3 4 53 Infinite numb

25 0 26 A horizontal force of 1 N is required to move a metal plate of area 10 m with a velocity of 2 10 m s when it rests on a layer of oil 1 5 x 10 2 m thick Find the coefficient viscosity of oil An electron in an atom is revolving around the nucleus in a circular orbit of radius 5 3 10 11 m with a speed of 2 x 106 m s Find the resultant orbital magnetic moment and angular momentum of the electron

5 21 The magnetic materials having negative magnetic susceptibility are A Non magnetic C Diamagnetic 5 22 The average and PMS B Para magnetic D Ferromagnetic

table The electric charge Q positive is uniformly distributed on a thin dielectric ring of mass m The ring lays on a frictionless shown in the figure The magnetic field is perpendicular to the plane of ring varies from 0 to some value of Bo Choose the correct statement as QBo A The angular velocity of ring will be 2m QBo B The angular velocity of ring will be C The angular velocity of ring will be D The angular velocity of ring will be 2m QBO 4m QBo 4m clockwise as viewed from above B anticlockwise as viewed from above clockwise as viewed from above anticlockwise as viewed from above

The diagram shows a U shaped wire ABCD hanging freely in rods X and Y are connected to a d c supply Which of the following is rue when switch S is closed A U shaped wire starts to oscillate to and fro moving in between the two bar magnets and away from the magnets 3 U shaped wire swing away from the magnets and stays at a position away from the magnets C U shaped wire swings inward towards the magnet and stays at a position in between the magnets Nothing happens to U shaped wire S N S D i X C N S A

15 Magnetic materials used for making permanent magne P and magnets in a transformer 7 have different propertic of the following which property best matches for the type o magnet required 2 Sept 2020 Morning A T Large retentivity small coercivity B P Small retentivity large coercivity C T Large retentivity large coercivity D P Large retentivity large coercivity 16 A perfo

A current carrying wire current i perpendicular to the plane of the paper produces a magnetic field as shown in the figure A square of side a is drawn with one of its vertices on the wire The integral B dr along PQR has the value A uoi Hoi 4 C B D Hoi 8 Hoi 2 P lines of B R Q

1 Find susceptibility of material whose dielectric constant is 2 26 2 The bound charge density and free charge density are 12 and 6 unit respectively Calculate susceptibility 3 The given equation satisfies Laplace equation v x y Z 4 Determine the charge that produce an electric field strength of 40 v cm at a distance 30 cm 5 A point charge 2 nc is located at origin what is the potential at 1 0 0

An electron and a positron are projected in a transverse magnetic field of strength B with speed v each If width of magnetic field region is kr where k is a constant ris radius of revolution of each of the particle Time spent by each of the particles in magnetic field is one fourth of the time period of revolution of particles for k equal to Assume elastic collision if particles collide a 1 c 5 Electron kr 1 5 r Positron b 2 d 2

Figure shows the cross sectional view of the hollow cylindrical conductor with inner radius R and outer radius 2R cylinder carrying uniformly distributed current i along its axis The magnetic induction at point P at a distance 3R 2 from the axis of the cylinder will be 2R R 3R 2 M

Consider the same situation as in the previous problem This time the magnet has mass 7 81 kg and the force pulling the magnet to the right has magnitude 128 0 N What is the magnitude of the tension force in the cord 283 0 N 195 0 N 149 2 N 204 6 N

A particle confined to move along x axis has a wave function y 3 x between x 0 and x 1 0 v 0 elsewhere Find the probability in percentage that the particle can be found between x 0 4 tox 06 15 2 23 6 60 40

Q 26 The magnitude of difference between mean value and each measured value is called as a Absolute error b random error c relative error d none of the above Q 27 The ratio of mean absolute error in the measurement of physical quantity to mean value is called a absolute error b relative error c random error d experimental error

A Electric monopoles do not exist whereas magnetic monopoles exist B Magnetic field lines due to a solenoid at its ends and outside cannot be completely straight and confined C Magnetic field lines are completely confined within a toroid D Magnetic field lines inside a bar magnet are not parallel E x1 is the condition for a perfect diamagnetic material where x is its magnetic susceptibility Choose the correct answer from the options given below B and D only A and B only C and E only B and C only Question Type MCQ Question ID 86435155 Ontion 1 ID 86435116

4 27 An electron is shot into one end of a solenoid As it enters the uniform magnetic field within the solenoid its speed is 800m s and its velocity vector makes an angle of 30 with the central axis of the solenoid The solenoid carries 4 04 current and has 8000 turn along its length Find number of revolutions made by the electron within the solenoid by the time it emerges from the solenoid s opposite end Charge to mass ratio e m for electron is 3 x 10 1 C kg Fill your answer in multiple of 10 A 1600 C 800 B 1200 D 600

The time period of a freely suspended magnetin uniform horizontal magnetic field B is T If this magnet of pole strength m is divided into four parts such that the length and width of each part is half that of initial one Then the time period of each part when suspended freely in same magnetic field will be 1 2T 2 T T T 3 4

The coercivity of a bar magnet is 100 A m It is to be demagnetised by placing it inside a solenoid of length 100 cm and number of turns 50 The current flowing in the solenoid will be 1 4 A 2 2 A 3 1 A

Illustration 15 The equivalent inductance of two inductors is 2 4 H when connected in parallel and 10 H when connected in series What is the value of inductances of the individual inductors

A ball of mass m falls vertically from a height h and collides with a block of equal mass m moving horizontally with a velocity v on a surface The coefficient of kinetic friction between the block and the surface is 0 2 while the coefficient of restitution e between the ball and the block is 0 5 There is no friction acting between the ball and the block The velocity of the block just after the collision decreases by A 0 5 2gh C 0 1 2gh B 0 D 0 3 2gh m A 0

13 Lorentz force can be calculated by using the formula a F q E V x B c F q E v B b F q E vxB d F q Exv B

D A bar magnet of magnetic moment M is placed at right angles to a magnetic induction B If a force F is experienced by each pole of the magnet the length of the magnet will be a MB F c MF B b BF M d FIMB MEET

Electric and magnetic forces determine the properties of at molecules and bulk matter

The work done in turning a magnet of magnetic moment M by an angle of 90 from the meridian is n times the corresponding work done to turn it through an angle of 60 where n is given by 1 1 2 3 1 4 2 2 4 1 6

6 A magnet is suspended in the magnetic meridian with an untwisted wire The upper end of the wire is rotated through 180 to deflect the magnet by 30 from magnetic meridian When this magnet is replaced by another magnet the upper end of the wire is rotated through 270 to deflect the magnet 30 from magnetic meridian The ratio of magnetic moments of magnet is A 1 5 B 5 8 C 1 8 D 8 5

Figure 38 Q5a shows a conducting loop being pulled out of a magnetic field with a speed v Which of the four plots shown in figure b may represent the power delivered by the pulling agent as a function of the speed v X X X X X X X X X X X X X X a X 10 V PI d a Cabol lato b b V

A bar magnet used in vibration magnetometer is heated to reduce the magnetic moment by all other changes in dimensions the time period of bar magnet in same magnetic field Increases by 25 Is not changed 1 Increases by 67 3 Increases by 12 2 4