MULTIPLE CHOICE QUESTIONS
Q.1 The study of magnetism produced by electric current and electric current produced
by changing magnetic field is called
A) Magnetic field C) Electric current
B) Electric and magnetic field D) Electromagnetism
Q.2 Magnetic force on a current carrying conductor is given by
A) IL B sin α C) IL B cos α
B) IL B tan α D) IL AB sin α
Q.3 Current carrying conductor experiences maximum magnetic force in a uniform
magnetic field when it is placed
A) Perpendicular to the field C) Parallel to the field
B) At 180
o D) At 60
o on the field
Q.4 Magnetic force per unit length on a current carrying conductor placed in a
magnetic field is __________ A) ILB C) ILB sin
B) IB D) None of these
Q.5 Magnetic flux and magnetic flux density are related as
A) magnetic flux density Magnetic flux =
area
C) Magnetic flux x flux density = area
B) magnetic flux Flux density =
area
D) Flux density = Magnetic flux x area
Q.6 The magnetic flux will be half of maximum when the angle between B
and A
is
A) 270
0 C) 60
0
B) 90
0 D) 0
0
Q.7 According to Ampere’s circuital law the magnetic field along the axis of solenoid
with n number of turns per unit length is given by
A) B o nI C) B o I
B) o I B
n
D) on B
I
Q.8 The force F = Fe + Fm in the accelerating force is
A) Magnetic force C) Lorentz force
B) Electric force D) Depends on nature of charge
Q.9 If an electron projected in a magnetic field with a velocity v, it will experience a
force given byA) qB
r
mv C) mv
r
qB
B) qmv
B
D) qmB
r
Q.11 The voltage applied across X plates displaces the spot along x-axis and displacement
is proportion to
A) Voltage C) Current
B) Time D) All of these
Q.12 The working of all D.C electric meters (ammeters, galvanometer and voltmeter)
based upon
A) Magnetic force exerted on the moving charge C) Chemical effect of current
B) Magnetic effect of current D) None of these
Q.13 The current passing through a coil of galvanometer is given by
A) c
BNA
C) c
AB
B) BAN
c
D) c A
BN
Q.14 The galvanometer in which the coil comes to rest quickly after the current passed
through it or the current is stopped from flowing through it is called
A) Stable galvanometer C) Dead beat galvanometer
B) Both a and b D) None of these
Q.15 The low current required to produce 1mm deflection on a scale placed 1m away
from mirror of galvanometer is called
A) Sensitivity of voltmeter C) Sensitivity of ohm meter
B) Sensitivity of ammeter D) Current sensitivity of galvanometer
Q.16 When charged particle enters in a magnetic field, at an angle other then 90
o
, then it
moves in
A) Circular path C) Straight line
B) Random form D) Helical path
Q.17 The e/m of a proton is
A) Same as electron C) Smaller then electron
B) Greater than electron D) All of these
Q.18 In CRO the grid is at___________ w.r.t anodes
A) Positive potential C) Negative potential
B) Both a and b D) Zero potential
Q.19 A charged particle is projected at an angle into a uniform magnetic field. Which is of
the following parameters of the charged particle will be affected by the magnetic field
A) Energy C) Momentum
B) Speed D) Velocity
Q.20 The brightness of the spot on CRO screen is controlled by
A) Cathode C) Anode
A) F e vB
C) F e vB ki
B) F e v.B
D) F e v.B
Q.10 When a charged particle enters a magnetic field it will move on a circular path of radiusB) Grid D) Plates
Q.21 Magnetic field
B = 4i +18k
Wbm-2 passes through
2 5k m area. Net flux through
the area is
A) 20 Wb C) 4 90 10
Wb
B) 90 Wb D) Zero
Q.22 A charged particle moving in a magnetic field experiences a resultant force
A) In the direction of the field
B) In the direction of its motion
C) In the direction opposite to its motion
D) In the direction perpendicular to field and its motion
Q.23 The deflection in the galvanometer falls from 50 divisions to 25 divisions when a 20
Ohm shunt is applicable. The galvanometer’s resistance is
A) 10 C) 20
B) 30 D) 40
Q.24 The force F acting on charge q moving in magnetic field B
r
with velocity v
r
is
F q v B
r r r
which of given quantities in a pair are right angle to each other
A) vand B
r r
C) vand F
r r
B) F and B
r r
D) Both “B” and “C” are correct
Q.25 Magnetic field at a point which is at a distance “r” from a current carrying
conductor through which current I is flowing is
A) B Ir B) 1 B
Ir
C) B
I
r
D) I B
r
Q.26 The SI unit of magnetic induction is tesla which is T=NA–1m–1
. It is related with
gauss G as
A) T=0.1 G C) T=10 G
B) T=1000 G D) T=10000 G
Q.27 The force on charge particle q moving with velocity v in magnetic field B
r
is
F q v B
r r r
. The work done by magnetic force on the particle
A) Depends upon v C) Depends upon B
B) Angle between v and B
r r
D) Zero
Q.28 There will be no force experienced if
A) Two parallel wires having current in same direction
C) Two parallel wires having current in opposite direction
B) A positive charge projected perpendicular in magnetic field
D) A positive charge projected along axis of solenoid
Q.29 Two parallel wires carrying current in same direction which figure shows correct
direction of magnetic force on theA) B) C) D)
Q.30 When a charge particle moves in magnetic field at angle 45° the trajectory of
charged particle is
A) Circle C) Straight line
B) Helix D) Parabola
Q.31 An electron beam passes straight through a region where magnetic and electric
fields are perpendicular to each other. If magnetic field is – –
3 2 2 10 Wbm and
electric field is –
.
4 1 3 4 10 Vm the velocity of electron is
A) 6.8×10
7ms
–1 C) 1.7×10
7ms
–1
B) 3.4×10
7ms
–1 D) 6.8×10
–7ms
–1
Q.32 A straight conductor carrying current I split into a circular loop
of radius r as shown in fig. The magnetic field at the center of
circle is:
A) 2
o I
r
B) 2
o I
r
C) o I
r
D) Zero
Q.33 In step up transformer, voltage in the secondary increases and power in secondary
A) Remain same C) Increases because current decreases
B) Decreases because voltage increases D) May increases if voltage remain same
Q.34 In CRO, the time base, circuit is connected to
A) Vertical plates C) Electron gun
B) Horizontal plates D) Fluorescent screen
Q.35 Due to current in straight conductor the distance between magnetic field lines
A) Increases away from conductor
B) Decreases away from conductor
C) Increases towards conductor
D) Decreases and then increases towards conductor
Q.36 A long straight current carrying conductor has current direction from bottom to top
when held vertically. What will be the direction of magnetic field lines when
observed from below the conductor?
A) Clockwise C) Anticlockwise
B) Vertically upward D) Vertically downward
Q.37 A unit of magnetic induction is
A) �𝑤�� �𝑔��−2 C) Weber/ampereeter
B) Weber/meter D) Weber
Q.38 Two parallel wires carrying currents in the same direction attract each other
because of
A) Potential difference between them C) Mutual inductance between them
B) Electric forces between them D) Magnetic forces between them
Q.39 The magnetic field lines in the middle of a solenoid are
A) Circles C) Parallel to the axis
B) Spirals D) Perpendicular to axis
Q.40 If we hold a current carrying solenoid in our right hand in such a way that the
fingers curl in the direction of current, then thumb will indicates the direction of
A) Electric field C) Gravitational field
B) Magnetic field D) Electromagnetic field
Q.41 A neutron, a proton, an electron and an � − 𝒑𝒂𝒓𝒕 enter a
region of uniform magnetic field with equal velocities. The
magnetic field is perpendicular to paper and directed into the
paper. The tracks of particles are labeled in figure. The neutron
follows the track
A) A C) B
B) C D) D
Q.42 In given diagram is the wire attracted or repelled by the loop?
A) Repel C) Remain stationary
B) Attract D) Depends on magnitude of current
Q.43 An electron is projected at right angle to a uniform electric field. In
the absence of other fields, in which direction is the electron deflected?
A) In the plane of the paper B) Out of the plane of the paper
B) To the left D) To the right
Q.44 When the charged particle is projected at right angles to the field, then force
experienced by it will be
A) Maximum C) q v B
B) Zero D) both A & C
Q.45 If the charge is free to move in an electric field, then the acceleration produced in it
is given by
A) ��� C) ��� B) �
��
D) ���
Q.46 When an electron is projected in a direction perpendicular to the lines of magnetic
force, its path becomes a
A) Circle C) Parabola
B) Straight line D) None of these
Q.47 Velocity of an electron accelerated by a potential difference V can be found by
A) 2�� � C) 2�� � C) �
2�� D) 2��� Q.48 Alpha particles are made to pass through a device called velocity selector. The
velocity of � − 𝒑𝒂𝒓𝒕� can be found by
A) � = �� C) � = �/�
B) � = �/� D) None of these
Q.49 A current carrying wire is placed between magnetic poles as
shown. The direction of magnetic force on it is
A) Out of the paper C) Into the paper
B) Towards North Pole D) Toward south pole