JEE Questions for Physics Moving Charges And Magnetism Quiz 8 - MCQExams.com

A beam of well collimated cathode rays travelling with a speed of 5 × 106 ms–1 enter a region of mutually perpendicular electric and magnetic fields and emerge undeviated from this region. If |B|= 0.02 T, the magnitude of the electric field is
  • 105 Vm–1
  • 2.5 × 108 Vm–1
  • 1.25 × 1010 Vm–1
  • 2 × 103 Vm–1
An electron is moving in the north direction. It experiences a force in vertically upward direction. The magnetic field at the position of the electron is in the direction of
  • East
  • West
  • North
  • South
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 depend 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
A charged particle of mass m and charge q describes circular motion of radius r in a uniform magnetic field of strength B. The frequency of revolution is

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  • 2)
    Physics-Moving Charges and Magnetism-82852.png

  • Physics-Moving Charges and Magnetism-82853.png

  • Physics-Moving Charges and Magnetism-82854.png
An electron is accelerated by a potential difference of 12000 volts. It then enters a uniform magnetic field of 10–3 T applied perpendicular to the path of electron. Find the radius of path. Given mass of electron = 9 × 10–31 kg and charge on electron = 1.6 × 10–19 C
  • 36.7 m
  • 36.7 cm
  • 3.67 m
  • 3.67 cm
The charge on a particle Y is double the charge on particle X. These two particles X and Y after being accelerated through the same potential difference enter a region of uniform magnetic field and describe circular paths of radii R1 and R2 respectively. The ratio of the mass of X to that of Y is

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  • 2)
    Physics-Moving Charges and Magnetism-82858.png

  • Physics-Moving Charges and Magnetism-82859.png

  • Physics-Moving Charges and Magnetism-82860.png
A particle with 10–11 coulomb of charge and 10–7 kg mass is moving with a velocity of 108 m/s along the y–axis. A uniform static magnetic field B = 0.5 tesla is acting along the x–direction. The force on the particle is

  • Physics-Moving Charges and Magnetism-82862.png
  • 2)
    Physics-Moving Charges and Magnetism-82863.png

  • Physics-Moving Charges and Magnetism-82864.png

  • Physics-Moving Charges and Magnetism-82865.png
A particle of charge qand mass m moving with a velocity v along the x–axis enters the region x>0 with uniform magnetic field B along the k ̂direction. The particle will penetrate in this region in the x–direction upto a distance d equal to
  • Zero
  • 2)
    Physics-Moving Charges and Magnetism-82867.png

  • Physics-Moving Charges and Magnetism-82868.png
  • Infinity
A charged particle is moving with velocity v in a magnetic field of induction B. The force on the particle will be maximum when
  • v and B are in the same direction
  • v and B are in opposite directions
  • v and B are perpendicular
  • v and B are at an angle of 45°
A charged particle enters a magnetic field H with its initial velocity making an angle of 45° with H. The path of the particle will be
  • A straight line
  • A circle
  • An ellipse
  • A helix
An electron and a proton enter a magnetic field perpendicularly. Both have same kinetic energy. Which of the following is true
  • Trajectory of electron is less curved
  • Trajectory of proton is less curved
  • Both trajectories are equally curved
  • Both move in straight-line path
A charged particle moves in a uniform magnetic field. The velocity of the particle at some instant makes an acute angle with the magnetic field. The path of the particle will be
  • A straight line
  • A circle
  • A helix with uniform pitch
  • A helix with non-uniform pitch
An electron is moving along positive x–axis. To get it moving on an anticlockwise circular path in x–y plane, a magnetic field is applied
  • Along positive y–axis
  • Along positive z–axis
  • Along negative y–axis
  • Along negative z–axis
A moving charge will gain energy due to the application of
  • Electric field
  • Magnetic field
  • Both of these
  • None of these
A proton, a deutron and an α–particle having the same kinetic energy are moving in circular trajectories in a constant magnetic field. If rp, rd and rα denote respectively the radii of the trajectories of these particles, then
  • rα = rpd
  • rα>rd>rp
  • rα = rd>rp
  • rp = rd = rα
When a magnetic field is applied in a direction perpendicular to the direction of cathode rays, then their
  • Energy decreases
  • Energy increases
  • Momentum increases
  • Momentum and energy remain unchanged
A charge moves in a circle perpendicular to a magnetic field. The time period of revolution is independent of
  • Magnetic field
  • Charge
  • Mass of the particle
  • Velocity of the particle
A proton of energy 200 MeV enters the magnetic field of 5 T. If direction of field is from south to north and motion is upward, the force acting on it will be
  • Zero
  • 1.6 × 10–10 N
  • 3.2 × 10–8 N
  • 1.6 × 10–6 N
An electron enters a region where magnetic (B) and electric (E) fields are mutually perpendicular to one another, then
  • It will always move in the direction of B
  • It will always move in the direction of E
  • It always possess circular motion
  • It can go undeflected also
A charge moving with velocity v in X-direction is subjected to a field of magnetic induction in the negative X-direction. As a result, the charge will
  • Remain unaffected
  • Start moving in a circular path in Y-Z plane
  • Retard along X-axis
  • Move along a helical path around X-axis
A positively charged particle moving due east enters a region a uniform magnetic field directed vertically upwards. The particle will
  • Get deflected vertically upwards
  • Move in a circular orbit with its speed increased
  • Move in a circular orbit with its speed unchanged
  • Continue to move due east
A particle moving in a magnetic field increases its velocity, then its radius of the circle
  • Decreases
  • Increases
  • Remains the same
  • Becomes half
A particle is moving in a uniform magnetic field, then
  • Its momentum changes but total energy remains the same
  • Both momentum and total energy remain the same
  • Both will change
  • Total energy changes but momentum remains the same

Physics-Moving Charges and Magnetism-82878.png
  • Zero
  • 2)
    Physics-Moving Charges and Magnetism-82879.png

  • Physics-Moving Charges and Magnetism-82880.png
  • None of these
The oscillating frequency of a cyclotron is 10 MHz. If the radius of its Dees is 0.5 m, the kinetic energy of a proton, which is accelerated by the cyclotron is
  • 10.2 MeV
  • 2.55 MeV
  • 20.4 MeV
  • 5.1 MeV
  • 1.5 MeV
A charged particle is moving in a uniform magnetic field in a circular path. Radius of circular path is R. When energy of particle is doubled, then new radius will be

  • Physics-Moving Charges and Magnetism-82883.png
  • 2)
    Physics-Moving Charges and Magnetism-82884.png
  • 2R
  • 3R
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
A charge q is moving in a magnetic field then the magnetic force does not depend upon
  • Charge
  • Mass
  • Velocity
  • Magnetic field
An electron moving towards the east enters a magnetic field directed towards the north. The force on the electron will be directed
  • Vertically upward
  • Vertically downward
  • Towards the west
  • Towards the south
An electron (mass = 9.0 × 10–31 kg and charge = 1.6 × 10–19 coulomb) is moving in a circular orbit in a magnetic field of 1.0 × 10–4weber/m2. Its period of revolution is
  • 3.5 × 10–7 sec
  • 7.0 × 10–7 sec
  • 1.05 × 10–6 sec
  • 2.1 × 10–6 sec
An electron (charge q coulomb) enters a magnetic field of H weber/m2 with a velocity of v m/s in the same direction as that of the field. The force on the electron is
  • Hqv newtons in the direction of the magnetic field
  • Hqv dynes in the direction of the magnetic field
  • Hqv newtons at right angles to the direction of the magnetic field
  • Zero

Physics-Moving Charges and Magnetism-82890.png
  • Go on moving in the same direction with increasing velocity
  • Go on moving in the same direction with constant velocity
  • Turn to its right
  • Turn to its left
In hydrogen atom, the electron is making 6.6 × 1015 rev/sec around the nucleus in an orbit of radius 0.528 Å. The magnetic moment (A–m2) will be
  • 1 × 10–15
  • 1 × 10–10
  • 1 × 10–23
  • 1 × 10–27
Two particles A and B of masses mA and mBrespectively and having the same charge are moving in a plane. A uniform magnetic field exists perpendicular to this plane. The speeds of the particles are vA and vBrespectively, and the trajectories are as shown in the figure. Then
Physics-Moving Charges and Magnetism-82891.png
  • mAvA< mBvA
  • mAvA> mBvB
  • mA< mB and vA< vB
  • mA = mB and vA = vB

Physics-Moving Charges and Magnetism-82893.png
  • 1
  • 1/2
  • 2
  • 1/4
A particle of mass 0.6 g and having charge of 25 nC is moving horizontally with a uniform velocity 1.2 × 104 ms–1 in a uniform magnetic field, then the value of the magnetic induction is (g = 10 ms–2)
  • Zero
  • 10 T
  • 20 T
  • 200 T
Motion of a moving electron is not affected by
  • An electric field applied in the direction of motion
  • Magnetic field applied in the direction of motion
  • Electric field applied perpendicular to the direction of motion
  • Magnetic field applied perpendicular to the direction of motion
At a specific instant emission of radioactive compound is deflected in a magnetic field. The compound can emit
(i) Electrons
(ii) Protons
(iii) He+2
(iv) Neutrons
The emission at the instant can be
  • i, ii, iii
  • i, ii, iii, iv
  • iv
  • ii, iii
Which particles will have minimum frequency of revolution when projected with the same velocity perpendicular to a magnetic field
  • Li+
  • Electron
  • Proton
  • He+
Mixed He+ and O2+ ions (mass of He+= 4 amu and that of O2+= 16 amu) beam passes a region of constant perpendicular magnetic field. If kinetic energy of all the ions is same then
  • He+ ions will be deflected more than those of O2+
  • He+ ions will be deflected less than those of O2+
  • All the ions will be deflected equally
  • No ions will be deflected

Physics-Moving Charges and Magnetism-82898.png

  • Physics-Moving Charges and Magnetism-82899.png
  • 2)
    Physics-Moving Charges and Magnetism-82900.png
  • Zero

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A particle of charge –16 × 10–18 coulomb moving with velocity 10ms–1 along the x–axis enters a region where a magnetic field of induction B is along the y–axis, and an electric field of magnitude 104 V/m is along the negative z–axis. If the charged particles continues moving along the x-axis, the magnitude of B is
  • 10–3 Wb/m2
  • 103 Wb/m2
  • 105 Wb/m2
  • 1016 Wb/m2
An electron and a proton have equal kinetic energies. They enter a magnetic field perpendicularly, then
  • Both will follow a circular path with same radius
  • Both will follow a helical path
  • Both will follow a parabolic path
  • All the statements are false
A proton of energy 8 eV is moving in a circular path in a uniform magnetic field. The energy of an alpha particle moving in the same magnetic field and along the same path will be
  • 4 eV
  • 2 eV
  • 8 eV
  • 6 eV
An electron, a proton, a deutron and an alpha particle, each having the same speed are in a region of constant magnetic field perpendicular to the direction of the velocities of the particles. The radius of the circular orbits of these particles are respectively Re, Rp, Rd and Rα. It follows that
  • Re = Rp
  • Rp = Rd
  • Rd = Rα
  • Rp = Rα
An electron moving with a uniform velocity along the positive x–direction enters a magnetic field directed along the positive y–direction. The force on the electron is directed along
  • Positive y–direction
  • Negative y–direction
  • Positive z–direction
  • Negative z–direction
An electron is projected along the axis of a circular conductor carrying some current. Electron will experience force
  • Along the axis
  • Perpendicular to the axis
  • At an angle of 4° with axis
  • No force experienced
A very high magnetic field is applied to a stationary charge. Then the charge experiences
  • A force in the direction of magnetic field
  • A force perpendicular to the magnetic field
  • A force in an arbitrary direction
  • No force
In case of Hall effect for a strip having charge Q and area of cross-section A, the Lorentz force is
  • Directly proportional to Q
  • Inversely proportional to Q
  • Inversely proportional to A
  • Directly proportional to A
A charged particle of mass m and charge q travels in a circular path of radius r that is perpendicular to a magnetic field B. The time taken by the particle to complete one revolution is

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    Physics-Moving Charges and Magnetism-82909.png

  • Physics-Moving Charges and Magnetism-82910.png

  • Physics-Moving Charges and Magnetism-82911.png
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