18
A thick current carrying cable of radius 'R' carries current 'I' uniformly distributed across its cross section. The variation of magnetic field B(r) due to the cable with the distance 'r' from the axis of the cable is represented by :
20
A long solenoid of 50 cm length having 100 turns carries a current of 2.5 A. The magnetic field at the centre of the solenoid is :
$$\left( {{\mu _0} = 4\pi \times {{10}^{ - 7}}Tm{{A}^{-1}}} \right)$$
21
Ionized hydrogen atoms and $$\alpha $$-particles with same momenta enters perpendicular to a constant magnetic field, B. The ratio of their radii of their paths rH : r$$\alpha $$ will be :
22
A cylinderical conductor of radius R is carrying a constant current. The plot of the magnitude of the magnetic field. B with the distane d from the centre of the conductor, is correctly represented by the figure :
23
A metallic rod of mass per unit length
0.5 kg m–1 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
24
Current sensitivity of a moving coil
galvanometer is 5 div/mA and its voltage
sensitivity (angular deflection per unit voltage
applied) is 20 div/V. The resistance of the
galvanometer is
26
An electron is moving in a circular path under the influence of a transverse magnetic field of 3.57 $$ \times $$ 10-2 T. If the value of e/m is 1.76 $$ \times $$ 1011 C kg$$-$$1, the frequency of revoluation of the electron is
27
A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the centre of the loop is B. It is then bent into a circular coil of n turns. The magnetic field at the centre of this coil of n turns will be
29
A long straight wire of radius $$a$$ carries a steady current $$I$$. The current is uniformly distributed over its cross-section. The ratio of the magnetic fields B and B', at radial distance $${a \over 2}$$ and 2$$a$$ respectively, from the axis of the wire is
30
A proton and an alpha particle both enter a region of uniform magnetic field B, moving at right angles to the field B. If the radius of circular orbits for both the particles is equal and the kinetic energy acquired by proton is 1 MeV, the energy acquired by the alpha particle will be
33
An electron moving in a circular orbit of radius r makes n rotations per second. The magnetic field produced at the centre has magnitude
AIPMT 2015 Cancelled Paper
34
In an ammeter 0.2% of main current passes through the galvanometer. If resistance of galvanometer is G, the resistance of ammeter will be
35
Two identical long conducting wires $$AOB$$ and $$COD$$ are placed at right angle to each other, with one above other such that $$O$$ is their common point for the two. The wires carry $$I$$1 and $$I$$2 currents, respectively. Point $$P$$ is lying at distance f from $$O$$ along a direction perpendicular to the plane containing the wires. The magnetic field at the point $$P$$ will be
37
A long straight wire carries a certain current and produces a magnetic field 2 $$ \times $$ 10$$-$$4 Wb m$$-$$2 at a perpendicular distance of 5 cm from the wire. An electron situated at 5 cm from the wire moves with a velocity 107 m/s towards the wire along perpendicular to it. The force experienced by the electron will be (charge on electron 1.6 $$ \times $$ 10$$-$$19 C)
38
When a proton is released from rest in a room, it starts with an initial acceleration $$a$$0 towards west. When it is projected towards north with a speed $$v$$0 it moves with an initial acceleration 3$$a$$0 towards west. The an initial accelearation 3a0 towards west. The an initial acceleration 3$$a$$0 toward west. The electric and magnetic fields in the room are
39
A proton carrying 1 MeV kinetic energy is moving in a circular path of radius R in uniform magnetic field. What should be the energy of an $$\alpha $$-particle to describe a circle of same radius in the same field?
40
An alternating electric field, of frequency $$v$$, is applied across the does (radius = R) of a cyclotron that is being used to accelerate protons (mass = m). The operating magnetic field (B) used in the cyclotron and the kinetic energy (K) of the proton beam, produced by it, are given by
41
Two similar coils of radius R are lying concentrically with their planes at right angles to each other. The currents flowing in them are $$I$$ and 2$$I$$, respectively. The resultant magnetic field induction at the centre will be
42
A milli voltmeter of 25 milli volt range is to be converted into an ammeter of 25 ampare range. The value (in ohm) of neccessary shunt will be
44
A galvanometer of resistance, G, is shunted by a resistance S ohm. To keep the main current in the circuit unchanged, the resistance to be put in series with the galvanometer is
45
Charge q is uniformly spread on a thin ring of radius R. The ring rotates about its axis with a uniform frequency $$f$$ Hz. The magnitude of magnetic induction at the center of the ring is
47
A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron
48
A current loop consists of two identical semicircular parts each of radius R, one lying in the x-y plane and the other in x-z plane. If the current in the loop is $$i$$. The resultant magnetic field due to the two semicircular parts at their common centre is
49
A closely wound solenoid of 2000 turns and area of cross-section 1.5 $$ \times $$ 10$$-$$4 m2 carries a current of 2.0 A. It is suspended through its centre and perpendicular to its length, allowing it to turn in a horizontal plane in a uniform magnetic field 5 $$ \times $$ 10$$-$$2 tesla making an angle of 30o with the axis of the solenoid. The torque on the solenoid will be
50
A particle having a mass of 10$$-$$2 kg carries a charge of 5 $$ \times $$ 10$$-$$8 C. The particle is given an initial horizontal velocity of 105 m s$$-$$1 in the presence of electric field $$\overrightarrow E $$ and magnetic field $$\overrightarrow B $$. To keep the particle moving in a horizontal direction, it is necessary that
(1) $$\overrightarrow B $$ should be perpendicular to the direction of velocity and $$\overrightarrow E $$ should be along the direction of velocity
(2) Both $$\overrightarrow B $$ and $$\overrightarrow E $$ should be along the direction of velocity
(3) Both $$\overrightarrow B $$ and $$\overrightarrow E $$ are mutually perpendicular and perpendicular to the direction of velocity.
(4) $$\overrightarrow B $$ should be along the direction of velocity and $$\overrightarrow E $$ should be perpendicular to the direction of velocity
Which one of the following pairs of statements is possible ?
51
A square current carrying loop is suspended in a uniform magnetic field acting in the plane of the loop. If the force on one arm of the loop is the net force on the remaining three arms of the loop is
52
A galvanometer has a coil of resistance 100 ohm and gives a full scale deflection for 30 mA current. If it is to work as a voltmeter of 30 volt range, the resistance required to be added will be
53
A galvanometer has a coil of resistance 100 ohm and gives a full scale deflection for 30 mA current. If it is to work as a voltmeter of 30 volt range, the resistance required to be added will be
54
Charge q is uniformly spread on a thin ring of radius R. The ring rotates about its axis with a uniform frequency $$f$$ Hz. The magnitude of magnetic induction at the center of the ring is
55
Under the influence of a uniform magnetic field, a charged particle moves with constant speed v in a circle of radius R. The time period of rotation of the particle
56
A galvanometer havings a coil resistance of 60 $$\Omega $$ shows full scale deflection when a current of 1.0 amp passes through it. It can be converted into an ammeter to read currents upto 5.0 amp by
57
The magnetic force acting on a charged particle of charge $$-$$2 $$\mu $$C in a magnetic frield of 2 T acting in y direction, when the particle velocity is $$\left( {2\widehat i + 3\widehat j} \right) \times {10^6}\,m{s^{ - 1}}$$
58
A galvanometer of resistance 50 $$\Omega $$ is connected to a battery of 3 V along with a resistance of 2950 $$\Omega $$ in series. A full scale deflection of 30 divisions is obtained in the galvanometer. In order to reduce this deflection to 20 divisions, the resistance in series should be
60
A particle of mass m, charge Q and kinetic energy T enters a transverse uniform magnetic field of induction $$\overrightarrow B $$. After 3 seconds the kinetic energy of the particle will be
61
The resistance of an ammeter is 13 $$\Omega $$ and its scale is graduated for a current upto 100 amps. After an additional shunt has been connected to this ammeter it becomes possible to measure currents upto 750 amperes by this meter. The value of shunt-resistance is
62
Under the influence of a uniform magnetic field, a charged particle moves with constant speed v in a circle of radius R. The time period of rotation of the particle
63
When a charged particle moving with velocity $$\overrightarrow v $$ is subjected to a magnetic field of induction $$\overrightarrow B $$, the force on it is non-zero. This implies that
64
Two circular coils 1 and 2 are made from the same wire but the radius of the 1st coil is twice that of the 2nd coil. What is the ratio of potential difference in volts should be applied across them so that the magnetic field at their centres is the same?
66
An electron moves in a circular orbit with a uniform speed v. It producess a magnetic field B at the centre of the circle. The radius of the circle is proportional to
67
To convert a galvanometer into a voltmeter one should connect a
68
A galvanometer of 50 ohm resistance has 25 divisions. A current of 4 $$ \times $$ 10$$-$$4 ampere gives a deflection of one division. To convert this galvanometer into a voltmeter having a range of 25 volts, it should be connected with a resistance of
69
A long solenoid carrying a current producess a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved, the new value of the magnetic field is
70
A charged particle moves through a magnetic field in a firection perpendicular to it. Then the
71
The magnetic field of given length of wire for single turn coil at its centre is B then its value for two turns coil for the same wire is
72
A charge q moves in a region where electric field and magnetic field both exist, then force on it is
73
To convert a galvanometer into a voltmeter one should connect a
74
An electron having mass m and kinetic energy E anter in uniform magnetic field B perpendiculaly, then its frequency will be
75
If number of turns, area and current through a coil is given by n, A and $$i$$ respectively then its magnetic moment will be
