JEE Questions for Physics Moving Charges And Magnetism Quiz 12 - MCQExams.com

The current sensitivity of a moving coil galvanometer can be increased by
  • Increasing the magnetic field of the permanent magnet
  • Increasing the area of the deflecting coil
  • Increasing the number of turns in the coil
  • Increasing the restoring couple of the coil
An electron and a proton are moving on straight parallel paths with same velocity. They enter a semi-infinite region of uniform magnetic field perpendicular to the velocity. Which of the following statement(s) is/are true
  • They will never come out of the magnetic field region
  • They will come out traveling along parallel paths
  • They will come out at the same time
  • They will come out at different times

Physics-Moving Charges and Magnetism-83317.png
  • If θ = 0°, the charge moves in a circular path in the x–z plane
  • If θ = 0°, the charge undergoes helical motion with constant pitch along the y–axis
  • If θ = 10°, the charge undergoes helical motion with its pitch increasing with time, along the y–axis
  • If θ = 90°, the charge undergoes linear but accelerated motion along the y–axis
Statement-I The sensitivity of a moving coil galvanometer is increased by placing a suitable magnetic material as a core inside the coil.
Statement-II Soft iron has a high magnetic permeability and cannot be easily magnetized or demagnetized.
  • Statement I is true, statement II is true; statement II is a correct explanation for statement I
  • Statement I is true, statement II is true; statement II is not a correct explanation for statement I
  • Statement I is true, statement II is false
  • Statement I is false, statement II is true
Advanced countries are making use of powerful electromagnets to move trains at very high speed. These trains are called maglev trains (abbreviated form magnetic levitation). These trains float on a guideway and do not run on steel tail tracks.
Instead of using an engine based on fossil fuels, they make use of magnetic field forces. The magnetized coils are arranged in the guideway which repel the strong magnets placed in the train\'s under carriage. This helps train move over the guideway, a technique called electrodynamic suspension. When current passes in the coils of guideway, a typical magnetic field is set up between the undercarriage of train and guideway which pushes and pulls the train along the guideway depending on the requirement.
The lack of friction and its aerodynamic style allows the train to move at very high speed
The force which makes maglev move is
  • Gravitational
  • Magnetic
  • Nuclear forces
  • Air drag
Advanced countries are making use of powerful electromagnets to move trains at very high speed. These trains are called maglev trains (abbreviated form magnetic levitation). These trains float on a guideway and do not run on steel tail tracks.
Instead of using an engine based on fossil fuels, they make use of magnetic field forces. The magnetized coils are arranged in the guideway which repel the strong magnets placed in the train\'s under carriage. This helps train move over the guideway, a technique called electrodynamic suspension. When current passes in the coils of guideway, a typical magnetic field is set up between the undercarriage of train and guideway which pushes and pulls the train along the guideway depending on the requirement.
The lack of friction and its aerodynamic style allows the train to move at very high speed
The disadvantage of maglev trains is
  • More friction
  • Less pollution
  • Less wear and tear
  • High initial cost
Advanced countries are making use of powerful electromagnets to move trains at very high speed. These trains are called maglev trains (abbreviated form magnetic levitation). These trains float on a guideway and do not run on steel tail tracks.
Instead of using an engine based on fossil fuels, they make use of magnetic field forces. The magnetized coils are arranged in the guideway which repel the strong magnets placed in the train\'s under carriage. This helps train move over the guideway, a technique called electrodynamic suspension. When current passes in the coils of guideway, a typical magnetic field is set up between the undercarriage of train and guideway which pushes and pulls the train along the guideway depending on the requirement.
The lack of friction and its aerodynamic style allows the train to move at very high speed
The levitation of the train is due to
  • Mechanical force
  • Electrostatic attraction
  • Electrostatic repulsion
  • Magnetic repulsion
A current loop ABCD is held fixed on the plane of the paper as shown in the figure. The arcs BC (radius = b) and DA (radius = a) of the loop are joined by two straight wires AB and CD. A steady current I is flowing in the loop. Angle made by AB and CD at the origin O is 30°. Another straight thin wire with steady current I1 flowing out of the plane of the paper is kept at the origin.
The magnitude of the magnetic field (B) due to the loop ABCD at the origin (O) is
Physics-Moving Charges and Magnetism-83320.png
  • Zero
  • 2)
    Physics-Moving Charges and Magnetism-83321.png

  • Physics-Moving Charges and Magnetism-83322.png

  • Physics-Moving Charges and Magnetism-83323.png
A current loop ABCD is held fixed on the plane of the paper as shown in the figure. The arcs BC (radius = b) and DA (radius = a) of the loop are joined by two straight wires AB and CD. A steady current I is flowing in the loop. Angle made by AB and CD at the origin O is 30°. Another straight thin wire with steady current I1 flowing out of the plane of the paper is kept at the origin.
Due to the presence of the current I1 at the origin
Physics-Moving Charges and Magnetism-83325.png
  • The forces on AB and DC are zero
  • The forces on AD and BC are zero

  • Physics-Moving Charges and Magnetism-83326.png

  • Physics-Moving Charges and Magnetism-83327.png

Physics-Moving Charges and Magnetism-83328.png
  • 5
  • 4
  • 3
  • 2

Physics-Moving Charges and Magnetism-83330.png
  • 7
  • 5
  • 4
  • 2
Two wires each carrying a steady current I are shown in four configurations in Column I. Some of the resulting effects are described in Column II. Match the statements in Column I with the statements in Column II
Physics-Moving Charges and Magnetism-83332.png

  • Physics-Moving Charges and Magnetism-83333.png
  • 2)
    Physics-Moving Charges and Magnetism-83334.png

  • Physics-Moving Charges and Magnetism-83335.png

  • Physics-Moving Charges and Magnetism-83336.png
Assertion Cyclotron does not accelerate electron.
Reason Mass of the electron is very small.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Cyclotron is a device which is used to accelerate the positive ion.
Reason Cyclotron frequency depends upon the velocity.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Magnetic field interacts with a moving charge and not with a stationary charge.
Reason A moving charge produces a magnetic field.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion If an electron is not deflected while passing through a certain region of space, then only possibility is that there is no magnetic region.
Reason Force is directly proportional to the magnetic field applied.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Free electrons always keep on moving in a conductor, even then no magnetic force acts on them in magnetic field unless a current is passed through it.
Reason The average velocity of free electrons is zero.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The ion cannot move with a speed beyond a certain limit in a cyclotron.
Reason As velocity increases time taken by ion increases.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The coil is bound over the metallic frame in moving coil galvanometer.
Reason The metallic frame helps in making steady deflection without any oscillation.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion A circular loop carrying current lies in XY plane with its center at origin having a magnetic flux in negative Z-axis.
Reason Magnetic flux direction is independent of the direction of current in the conductor.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • (nn) If Assertion is false but Reason is true.
Assertion The magnetic field produced by a current carrying solenoid is independent of its length and cross-sectional area.
Reason The magnetic field inside the solenoid is uniform.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion If an electron, while coming vertically from outerspace, enter the earth\'s magnetic field, it is deflected towards west.
Reason Electron has negative charge.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion A direct current flowing through a metallic rod produces magnetic field only outside the rod.
Reason There is no flow of charge carriers inside the rod.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion An electron and a proton enters a magnetic field with equal velocities, then, the force experienced by the proton will be more than electron.
Reason The mass of proton is 1837 times more than electron.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Torque on the coil is the maximum, when coil is suspended in a radial magnetic field.
Reason The torque tends to rotate the coil on its own axis.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Magnetic Resonance Imaging (MRI) is a useful diagnostic tool for producing images of various parts of human body.
Reason Protons of various tissues of the human body play a role in MRI.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The magnetic field at the ends of a very long current carrying solenoid is half of that at the center.
Reason If the solenoid is sufficiently long, the field withing it is uniform.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion If a charged particle is moving in a circular path in a perpendicular magnetic field, the momentum of the particle is not changing.
Reason Velocity of the particle in not changing in the magnetic field.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion If a proton and an a-particle enter a uniform magnetic field perpendicularly, with the same speed, then the time period of revolution of the a-particle is double than that of proton.
Reason In a magnetic field, the time period of revolution of a charged particle is directly proportional to mass.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.

Physics-Moving Charges and Magnetism-83346.png
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true.
A horizontal straight wire 10 m long extending from east to west falling with a speed of 5.0 m/s, at right angles to the horizontal component of the earth\'s magnetic field of strength 0.30 × 10–4wb/m2. The instantaneous value of the induced potential gradient in the wire, from west to east, is
  • +1.5 × 10–3 V/m
  • –1.5 × 10–3 V/m
  • +1.5 × 10–4 V/m
  • –1.5 × 10–4 V/m
he figure shows three straight wires P, Q and R carrying currents normal to the plane of the paper. All three current have the same magnitude. Which arrow best shows the direction of the resultant force on the wire P?
Physics-Moving Charges and Magnetism-83351.png
  • A
  • B
  • C
  • D
Figure shows a straight wire of length lcarrying i. The magnitude of magnetic field produced by the current at point P is
Physics-Moving Charges and Magnetism-83353.png

  • Physics-Moving Charges and Magnetism-83354.png
  • 2)
    Physics-Moving Charges and Magnetism-83355.png

  • Physics-Moving Charges and Magnetism-83356.png

  • Physics-Moving Charges and Magnetism-83357.png
A winding wire which is used to frame a solenoid can bear a maximum 10 A current. If length of solenoid is 80 cm and it\'s cross sectional radius is 3 cm, then required length if winding wire is (B = 0.2 T)
  • 1.2 × 102 m
  • 4.8 × 102 m
  • 2.4 × 103 m
  • 6 × 103 m
A current carrying wire LNis bent in the from shown below. If wire carries a current of 10 A and it is placed in a magnetic field of 5 T which acts perpendicular to the paper outwards then it will experience a force
Physics-Moving Charges and Magnetism-83360.png
  • Zero
  • 5 N
  • 30 N
  • 20 N
A wire of length L is bent in the form of a circular coil and current i is passed through it. If this coil is placed in a magnetic field then the torque acting on the coil will be maximum when the number of turns is
  • As large as possible
  • Any number
  • 2
  • 1
A particle having a charge of 10.0 μC and mass 1 μg moves in a circle of radius 10 cm under the influence of a magnetic field of induction 0.1T. When the particle is at a point P, a uniform electric field is switched on so that the particle starts moving along the tangent with a uniform velocity. The electric field is
Physics-Moving Charges and Magnetism-83363.png
  • 0.1 V/m
  • 1.0 V/m
  • 10.0 V/m
  • 100 V/m

Physics-Moving Charges and Magnetism-83365.png
  • 3 : 4
  • 11 : 7
  • 7 : 11
  • 5 : 3
Two circular coils X and Y, having equal number of turns, carry equal currents in the same sense and subtend same solid angle at point O. If the smaller coil X is midway between O and Y, and if we represent the magnetic induction due to bigger coil Y at O as BY and that due to smaller coil X at Oas BX, then
Physics-Moving Charges and Magnetism-83367.png

  • Physics-Moving Charges and Magnetism-83368.png
  • 2)
    Physics-Moving Charges and Magnetism-83369.png

  • Physics-Moving Charges and Magnetism-83370.png

  • Physics-Moving Charges and Magnetism-83371.png
A fixed horizontal wire carries a current of 200 A. Another wire having a mass per unit length 10–2 kg/m is placed below the first wire at a distance of 2 cm and parallel to it. How much current must be passed through the second wire if it floats in air without any support? What should be the direction of current in it?
  • 25 A (direction of current is same to first wire)
  • 25 A (direction of current is opposite to first wire)
  • 49 A (direction of current is same to first wire)
  • 49 A (direction of current is opposite to first wire)
Find magnetic field at O
Physics-Moving Charges and Magnetism-83374.png

  • Physics-Moving Charges and Magnetism-83375.png
  • 2)
    Physics-Moving Charges and Magnetism-83376.png

  • Physics-Moving Charges and Magnetism-83377.png
  • Zero
A square loop of side \'a\' hangs from an insulating hanger of spring balance. The magnetic field of strength B occurs only at the lower edge. It carries a current I. Find the change in the reading of the spring balance if the direction of current is reversed
Physics-Moving Charges and Magnetism-83379.png

  • Physics-Moving Charges and Magnetism-83380.png
  • 2)
    Physics-Moving Charges and Magnetism-83381.png

  • Physics-Moving Charges and Magnetism-83382.png

  • Physics-Moving Charges and Magnetism-83383.png

Physics-Moving Charges and Magnetism-83385.png
  • Fm = 1.2 N along +ve x–direction
  • Fm = 1.2 N along –ve x–direction
  • Fm = 1.2 N along +ve y–direction
  • Fm = 1.2 N along –ve y–direction
Five very long straight wires are bound together to form a small cable currents carried by the wires are I1 = 20 A, I2 = –6 A, I3 = 12 A, I4 = –7 A, I5 = 18 A. The magnetic induction at a distance of 10 cm from the cable is
  • 34 μT
  • 74 mT
  • 34 mT
  • 74μT
Following figure shows the path of an electron that passes through two regions containing uniform magnetic fields of magnitudes B1 and B2. It\'spath in each region is a half circle, choose the correct option
Physics-Moving Charges and Magnetism-83388.png
  • B1 is into the page and it is stronger than B2
  • B1 is into the page and it is weaker than B2
  • B1 is out of the page and it is weaker than B2
  • B1 is out of the page and it is stronger than B2
The square loop ABCD, carrying a current i, is placed in uniform magnetic field B, as shown. The loop can rotate about the axis XX\'. The plane of the loop makes an angle θ (θ < 90°) with the direction of B. Through what angle will the loop rotate by itself before the torque on it becomes zero
Physics-Moving Charges and Magnetism-83390.png
  • θ
  • 90°– θ
  • 90°+ θ
  • 180° – θ
A cylindrical conductor of radius \'R\' carries a current \'i\'. The value of magnetic field at a point which is R/4distance inside from the surface is 10 T. Find the value of magnetic field at point which is 4R distance outside from the surface

  • Physics-Moving Charges and Magnetism-83392.png
  • 2)
    Physics-Moving Charges and Magnetism-83393.png

  • Physics-Moving Charges and Magnetism-83394.png

  • Physics-Moving Charges and Magnetism-83395.png
Three long straight wires are connected parallel to each other across a battery of negligible internal resistance. The ratio of their resistances are 3 : 4 : 5. What is the ratio of distances of middle wire from the others if the net force experienced by it is zero
  • 4 : 3
  • 3 : 1
  • 5 : 3
  • 2 : 3
A horizontal metal wire is carrying an electric current from the north to the south. Using a uniform magnetic field, it is to be prevented from failing under gravity. The direction of this magnetic field should be towards the
  • North
  • South
  • East
  • West
If a long hollow copper pipe carries a direct current, the magnetic field associated with the current will be
  • Only inside the pipe
  • Only outside the pipe
  • Neither inside nor outside the pipe
  • Both inside and outside the pipe
0:0:1


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