JEE Questions for Physics Moving Charges And Magnetism Quiz 2 - MCQExams.com

Which of the following while in motion cannot be deflected by magnetic field?
  • Protons
  • Cathode rays
  • α - particles
  • Neutrons
Identify the correct statement from the following.
  • Cyclotron frequency is dependent on speed of the charged particle
  • Kinetic energy of charged particle in cyclotron does not dependent on its mass
  • Cyclotron frequency does not depend on speed of charged particle
  • Kinetic energy of charged particle in cyclotron is independent of its charge
The magnetic force on a charged particle moving in the field does not work, because
  • kinetic energy of the charged particle does not change
  • the charge of the particle remains same
  • the magnetic force is parallel to velocity of the particle
  • the magnetic force is parallel to magnetic field
When deuterium and helium are subjected to an accelerating field simultaneously then
  • both acquire same energy
  • deuterium accelerates faster
  • helium accelerates faster
  • Neither of them is accelerated
The cyclotron frequency of an electron grating in a magnetic field of 1 T is approximately
  • 28 MHz
  • 280 MHz
  • 2.8 GHz
  • 28 GHz
A proton and a deuteron with the same initial kinetic energy enter a magnetic field in a direction perpendicular to the direction of the field. The ratio of the radii of the circular trajectories described by them is
  • 1 : 4
  • 1 : √2
  • 1 : 1
  • 1 : 2
An electron and proton having same kinetic energy enter into magnetic field perpendicular to it. Then
  • the path of electron is less curved
  • the path of proton is less curved
  • both have equal curved paths
  • both have straight line paths
Positively charged particles are projected into a magnetic field. If the direction of the magnetic field is along the direction of motion of the charge particles, the particles get
  • accelerated
  • decelerated
  • deflected
  • no charged in velocity
The radius of the path of an electron moving at a speed of 3 × 107 m/s perpendicular to a magnetic field 5 × 10- 4 T is nearly
  • 27 cm
  • 15 cm
  • 45 cm
  • 34 cm
The maximum velocity to which a proton can be accelerated in a cyclotron of 10 MHz frequency and radius 50 cm is
  • 6.28 × 108 m/s
  • 3.14 × 108 m/s
  • 6.28 × 107 m/s
  • 3.14 × 107 m/s
If a particle of charge 10-12 C moving along the x-direction with a velocity of 105m/s experience a force of 10-10 N in y-direction due to magnetic field, then the minimum value of magnetic field is
  • 6.25 × 103 T in z-direction
  • 10-15 T in z - direction
  • 6.25 × 10-3 T in z-direction
  • 10-3 T in z - direction
A long horizontally fixed wire carries a current of 100 A. Directly above and parallel to it is a fine wire that carries a current of 20 A and weighs 0.04 N/m. The distance between the two wires for which the upper wire is just supported by magnetic repulsion is
  • 10-2 mm
  • 10-2 cm
  • 10-2 m
  • 10-2 km
The force between two parallel current carrying wires is independent of
  • their distance of separation
  • the length of the wires
  • the magnitude of currents
  • the radii of the wires
  • the medium in which they are placed
Assertion (A) When radius of circular loop carrying current is doubled, its magnetic moment becomes four times.
Reason (R) Magnetic moment depends on area of the loop.
  • Both A and R are true and R is the correct explanation of A
  • Both A and R are true but R is not the correct explanation of A
  • A is true but R is false
  • A is false but R is true
A tangent galvanometer is connected directly to an ideal battery. If the number of turns in the coil is doubled, the deflection will
  • increase
  • decrease
  • remain unchanged
  • either increase or decrease
3A of current is flowing in a linear conductor having a length of 40 cm. The conductor is placed in a magnetic field of strength 500 gauss and makes an angle of 30° with direction of the field. It experiences a force of magnitude
  • 3 × 104 N
  • 3 × 102 N
  • 3 × 10-2 N
  • 3 × 10-4 N
The magnetic dipole moment of a current loop is independent of
  • magnetic field in which it is lying
  • number of turns
  • area of the loop
  • current in the loop
A current carrying straight wire is kept along the axis of a circular loop carrying a current. The straight wire
  • will exert an inward force on the circular loop
  • will exert an outward force on the circular loop
  • will exert a force on the circular loop parallel to itself
  • will not exert any force on the circular loop
A conduction rod of 1 m length and 1 kg mass is suspended by two vertical wires through its ends. An external magnetic field of 2 T is applied normal to the rod. Now the current to be passed through the rod so as to make the tension in the wires zero is (take, g =10ms-2)
  • 0.5 A
  • 15 A
  • 5 A
  • 1.5 A
  • 2.5 A
The electrons in the beam of a television tube move horizontally from South to North. The vertical component of the earth's magnetic field points down. The electron is deflected towards
  • west
  • no deflection
  • East
  • North to South
Graph of force per unit length between two long parallel currents carrying conductor and the distance between them is
  • straight line
  • parabola
  • ellipse
  • rectangular hyperbola
A current is passed through a straight wire. The magnetic field established around it has its lines of forces.
  • elliptical
  • circular
  • oval
  • parabolic
The magnetic moment of atomic neon is equal to
  • zero
  • 2)
    Physics-Moving Charges and Magnetism-82293.png
  • μB

  • Physics-Moving Charges and Magnetism-82294.png
Ratio of magnetic field induction at the centre of a current carrying coil of radius r and at a distance 3r on its axis is

  • Physics-Moving Charges and Magnetism-82295.png
  • 2)
    Physics-Moving Charges and Magnetism-82296.png

  • Physics-Moving Charges and Magnetism-82297.png

  • Physics-Moving Charges and Magnetism-82298.png
A solenoid of 1.5 m length and 4.0 cm diameter possess 10 turns per cm. A current of 5 A is flowing through it.The magnetic field induction at axis inside the solenoid is
  • 2π × 10-4T
  • 2π × 10-5T
  • 20 π G
  • 2π G

Physics-Moving Charges and Magnetism-82301.png
  • 45o
  • 90o
  • 180o
  • 30o
A beam of protons is moving parallel to a beam of electrons. Both the beams will tend to
  • repel each other
  • come closer
  • move more apart
  • either ‘2’ or ‘3’
A charged particle enters at 30o to the magnetic field. Its path becomes
  • circular
  • helical
  • elliptical
  • straight line
An electron having a charge e moves with a velocity v in X–direction. An electric field acts on it in Y – direction. The force on the electron acts in
  • positive direction Y – axis
  • negative direction of Y – axis
  • positive direction of Z – axis
  • negative direction of Z – axis

Physics-Moving Charges and Magnetism-82303.png
  • always zero
  • never zero

  • Physics-Moving Charges and Magnetism-82304.png

  • Physics-Moving Charges and Magnetism-82305.png
A proton and an α – particle enter a uniform magnetic field perpendicular with the same speed. If proton takes 20μ seconds to make 5 revolutions, then the periodic time for the α – particle would be
  • 5μ sec
  • 8μ sec
  • 10μ sec
  • 16μ sec
A straight wire of length 1.0 m and carrying current of 1.2 A is placed in a uniform magnetic field of induction 2T. The magnetic field is perpendicular to the length of the wire.The force on the wire is
  • 2N
  • 1.2 N
  • 3 N
  • 2.4 N
An electron moves in a circular arc of radius 10 m at a constant speed of 2 × 107 ms-1 with its plane of motion normal to a magnetic flux density of 10-5 T. What will be the value of specific charge of the electron ?
  • 2 ×104C kg-1
  • 2×105C kg-1
  • 5×106C kg
  • 2×1011C kg-1
Which has greater resistance?
  • Voltmeter has more resistance
  • Millivoltmeter has more resistance
  • Both have same resistance
  • Depends on size of meter coil
The deflection in moving coil galvanometer falls from 50 divisions to 10 divisions, when a shunt of 12 Ω is applied, the resistance of the galvanometer coil is
  • 24 Ω
  • 12 Ω
  • 50 Ω
  • 48 Ω
In a shunted ammeter, only 10% of current passes through the galvanometer of resistance G. The resistance of the shunt is
  • 9 G
  • 10 G
  • G/9
  • G/10
A voltmeter has resistance of 2000 Ω and it can measure upto 2V. If we want to increase its range by 8V, then required resistance in series will be
  • 4000Ω
  • 6000Ω
  • 7000Ω
  • 8000Ω
The radius of curvature of the path of the charged particle in a uniform magnetic field is directly proportional to
  • the charge on the particle
  • the momentum of the particle
  • the energy of the particle
  • the intensity of the field.
Four wire loops each of length 2.0 metres are bent into four loops P.Q.R and S and then suspended in a uniform magnetic field. Same current is passed in each loop. Which statement is correct ?
Physics-Moving Charges and Magnetism-82312.png
  • Couple on loop P will be the highest
  • Couple on loop Q will be the highest
  • Couple on loop R will be the highest
  • Couple on loop S will be the highest
Cathode rays and canal rays produced in a certain discharge tube are deflected in the same direction, if
  • a magnetic field is applied normally
  • an electric field is applied normally
  • an electric field is applied tangentially
  • a magnetic field is applied tangentially.
Magnetic field induction at the centre of the coil of 50 turns, radius 0.5 m and carrying a current of 2 A is
  • 0.5 ×10-5 T
  • 1.25 × 10-4 T
  • 3 × 10-5 T
  • 4 × 10-5 T.
A wire of length 2 m carries a current of 1 ampere is bend to form a circle. The magnetic moment of the coil is
  • 2π
  • π/2
  • π/4
  • 1/π
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

  • Physics-Moving Charges and Magnetism-82314.png
  • 2)
    Physics-Moving Charges and Magnetism-82315.png
  • 4B
  • 2B
A long solenoid has n turns per metre and current I ampere is flowing through it. The magnetic field at the ends of solenoid is
Physics-Moving Charges and Magnetism-82317.png
  • μ0nI/2
  • μ0nI
  • zero
  • 2μ0nI
A long solenoid carrying a current produces 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 magnetic field is
  • B/2
  • B
  • 2B
  • 4B
Two thin metallic strips, carrying current in the direction shown, cross each other perpendicularly without touching but being close to each other, as shown in the Fig. The regions which contain some points of zero magnetic induction are
Physics-Moving Charges and Magnetism-82320.png
  • I and II
  • I and III
  • I and IV
  • II and III

Physics-Moving Charges and Magnetism-82321.png
  • v > u, y < 0
  • v = u , y > 0
  • v > u, y > 0
  • v = u, y < 0
Three long straight wires A, B and C are carrying currents as shown in fig. The resultant force on B is directed
  • perpendicular to the plane of paper and outwards
  • perpendicular to the plane of paper and inwards
  • towards A
  • towards C
A one mettre long wire is lying at right angles to the magnetic field. A force of 1 kg wt is acting on it in a magnetic field of 0.98 tesla. The current flowing in it will be
  • 100 A
  • 10 A
  • 1 A
  • zero
A galvanometer has 30 divisions and a sensitivity 16 μA/div. it can be converted in to a voltmeter to read 3 V by connecting
  • resistance nearly 6 k Ω in series
  • 6 k Ω in parallel
  • 500 Ω in series
  • 6.6 k Ω in series
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