Magnetism and Matter Questions and Answers

A neutron a proton an electron and an a particle enter a region of uniform magnetic field with equal velocities The magnetic field is perpendicular directed into the paper The tracks of particles are labelled in fig The electron follows track 1 A 2 B X X X X X X X X X X X X x X X X X X X C X X X X X X X X 3 X X

On placing a piece of ferromagnetic material of cross sectional area 1 cm in magnetic field of 200 oersted flux density of 3000 Gauss is produced in it The values of relative permeability and magnetic material susceptibility of the respectively be A 11 9 and 150 C 50 and 11 9 B 150 and 11 9 D 15 and 14

2 Which of the following conclusions can be draw from the result 4B d 0 1 magnetic field is zero everywhere 2 magnetic monopole cannot exist 3 magnetic lines of forces do not intersectea 4 a current produces magnetic field

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 2 2 M 60 r MIE 3 M 2 4 M TO

of each pole is 2 2x Am 4 10x Am substance with magnetic 1 2Am G 4x Am A ferromagnetic susceptibility 7 99 cross sectional area A 200 cm and length L 50cm is placed in vacuom in an external magnetic field B 16x pT then the magnetising intensity at the center of ferromagnetic substance will be 1 04 A m 2 40 A m

3 Time period of vibration of a bar magnet in uniform magnetic field is T If the magnet is cut parallel to its length into two identical parts then time period of vibration of one part in same magnetic field is 1 T Ons 2

25 a Earth can be thought of as a sphere of radius 6400 km Any object or a person is performing circular motion around the axis of earth due to earth s rotation period 1 day What is acceleration of object on the surface of the earth at equator towards its centre what is it at latitude How does these accelerations compare with g 9 8 m s

1 0 207 x 10 5 m 2 2 07 x 10 m 3 20 7 x 10 5 m 9 The resistivity p of a Germanium sample is measured at 300K The sample is then remelted and dopped with 4 4 x 1016 arsenic atom cm3 The new crystal has resistivity of 0 12 cm and is n type 2 3000cm Vs 1 The original sample was N type with resitivity 0 0094 cm 2 The original sample was p type with resistivity 0 0094 cm 3 The original sample was N type with resistivity 0 179 cm 4 The original sample was P type with resistivity 0 179 cm resistivly drops to 10 of

If current is passed in a spring then 1 Gets compressed 2 Gets expanded 3 Oscillates

A square coil free to rotate about y axis of side a carrying current l and is having one of its side AB parallel to y axis and its plane is at angle 30 with x axis as shown If a uniform magnetic field E exist in the region along x direction then torque due to magnetic force on the coil is and the loop will rotate toward the x axis and the loop will rotate toward the z axis 3 ia B and the loop will rotate toward the x axis 2 4 Via B and the loop will rotate toward the 2 axis 2

A bar magnet is made to fall through a long vertical copper tube The speed v of the magnet as a function of time t is best represented by 1 a 3 C V d a b C 2 b 4 d

8 9 that depends on the ratio of the loop rad There are two loops A and B placed coaxially along vertical line Loop A is allowed to fall freely towards loop B If constant current flowing in loop A is as shown in the figure then find the direction of flow of induced current in loop B as seen from the bottom of loop B A B 1 Clockwise 2 Anticlockwise 3 No current will induce 4 Can t be determined Aakash Educational Services Limited Regd Office Aakash Tower 8 Pusa Road New Delhi 110005 Ph 011 47623456

A small bar magnet is dropped into a vertical copper tube of infinite length then the bar magnet moves inside the tube with g acceleration due to gravity 1 An acceleration equal to g 2 An acceleration less than g 3 An acceleration greater than g 4 Initially acceleration less than g and finally no oration

1 The frequency of vibration in a vibration magnetometer of the combination of two bar magnets of magnetic moments M and M is 6 Hz when like poles are tied and it is 2 Hz when the unlike poles are tied together then the ratio M M is a 4 5 b 5 4 c c 1 3 d 3 1

30 A bar magnet has magnetic moment M If a hole is drilled normally through the centre of length of magnet then the new magnetic moment of the magnet is 1 Less than M 3 Equal to M 2 More than M 4 Cannot he prodit

Determine the direction of the induced current in coil A in the following figures from the right side A B J J SN J A C NS SN D NS

40 A linear magnet of magnetic moment M is bent in arc as shown in the given figure New magnetic moment is 1 M 3 3M TU N 60 2 4 S 2M TC 5M TU

2 A magnetic dipole of magnetic moment 0 72 A m is placed horizontally with the north pole pointing towards south Find the position of the neutral point if the horizontal component of the earth s magnetic field is 18 UT

BIL 3 Length of helicopter s rotor s blade is 3 5 m It is rotating with 4 rev sec At this place magnetic field of earth is 0 52 x 104 T and dip angle is 60 then potential difference will be 1 13 8 mV 2 6 9 mV

The magnetic field 0 225 m from a wire is 4 29 x 10 7 T How much current is flowing through the wire A

Which of the following are characteristics of magnets 1 Like poles repel each other 2 Magnets always have two poles 3 Like poles attract each other 4 Opposite poles repel each other 1 and 4 Only 2 1 and 2 Oply 1

3 Explain what the barrier potential is and how it is created 4 Describe the process of doping and explain how it alters the atomic structure of silicon 5 An intrinsic Silicon has 1 billion free electrons at room temperature If the temperature doubles how many holes will be there

9 Explain the process to get electricity running through a solenoid with only a magnet 10 What is the difference between a generator and a motor Important

9 The magnetic field in the Crab Nebula is about 1x10 8 T If an electro perpendicularly to this field is affected by a magnetic force of 3 2x10 22 N what is the electron s speed moving

a a b b 12 mH 24 mH 9 mH 20 mH 30 mH 8 mH 25 H 60 H 10 mH 30 pH 15 uH 15 mH2 m 158 batoon 18 uH 75 uH 20 kH 38 H 12 F

latitude 3 attempts left What is the latitude of an observer who measures an altitude of the Sun above the northern horizon of 102 0 at noon on the winter solstice select Check my work

latitude What is the latitude of an observer who measures an altitude of the Sun above the northern horizon of 102 0 at noon on the winter solstice O 3 attempts left select Check my work

V Enter your answer in scientific notation What is the rotational velocity at a latitude at which the Earth s circumference is 2 840 104 km in km h Assume a sidereal day x 10 attempts left km h Check my work

As shown below two wires are carrying current into the plane of the paper Current one is i 17 0 A while current two is i 21 0 A What is the magnitude and direction of th magnetic field found at the point X which is a distance d 3 23 x 10 m to the right of current one and also a distance d 1 17 x 104 m to the left of current two i 17 0 A i 21 0 A elect one a O b d 3 23 x 10 4 m Fy ZO 2 54 x 10 2 T y 4 64 x 10 2 Ty x TO d 1 17 x 10 4 m

A 15 turn rectangular loop of wire of width 10 cm and length 20 cm has a current of 2 5 A flowing through it Two sides of the loop are oriented parallel to a uniform magnetic field of strength 0 037 T and the other two sides are perpendicular to the magnetic field a What is the magnitude of the magnetic moment of the loop b What torque does the magnetic field exert on the loop

4. Which of the following are true regarding Earth's magnetic field? Check all that apply. the magnetic north pole is south of the geographical north pole the magnetic north pole drifts about 1100 km in a century the magnetic poles drift in an elliptical pattern daily the magnetic north pole lines up exactly with the geographical north pole

Which of the following statement(s) is/are incorrect? (a) In a solenoid, the net magnetic field is the vector sum of the fields due to all the turn (b) Enamelled wires are used for winding, so that turns are insulated from each other. (c) The field inside the solenoid approaches zero and everywhere outside becomes parallel to the axis. (d) The solenoid is commonly used to obtain uniform magnetic field.

Two magnets are placed near each other on a space station orbiting Earth. Their north and south poles are facing each other. Which statement explains what will happen to the magnets A. They will be attracted because they are in each other's electric field. B. They will be attracted because they are in each other's magnetic field. C. They will be repelled because they are in each other's gravitational field. D. They will be repelled because they are in each other's magnetic field.

IV Go to Listen with Varying Air Pressure tab. 1. What can you hear when the pressure is at 1 atm? 2. Now remove the air from the box and record what happens. 3. What can you conclude about sound in a vacuum? Why do you think this happens?

When two transverse waves traveling through a medium meet and exactly coincide, the resulting displacement of the medium Select one: a. is the sum of the displacements of each wave. b. is zero. c. is always destructive. d. is always greater than the displacement of either wave alone.

The fundamental (m= 1) frequency for a pipe with closed - open boundaries is 100 Hz. Select each frequency below that will also be a resonant frequency for this pipe. 50 Hz 150 Hz 200 Hz 300 Hz 400 Hz 500 Hz

Consider a long (aka infinite) conducting wire, with a diameter of 1 mm. It is charged with a linear charge density of +8 nC/m. There also exists a point charge of 13 nC at a distance of 4cm above the wire. What is the electric field at point P, 8 cm below the wire? What is the maximum mass of a -15nC point charge such that it is suspended in place at point P? (Hint for second question, you are balancing the electric force and gravity.)

In the structure shown below, all flux lines in the core are assumed to cross the air gap. The structure dimensions are as follows: core cross-sectional area Am = 20 cm2, mean-path length em = 40 cm, eg = 2 mm, and N = 75 turns. The iron-core permeability can be assumed to be constant with ur = 4500. The coil current i (-30 A) is below the saturation level. Calculate the flux density in the air gap, (a) including the reluctance of the core as well as that of the air gap and (b) ignoring the core reluctance in comparison to the reluctance of the air gap.