JEE Questions for Physics Moving Charges And Magnetism Quiz 14

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 2I, respectively. The resultant magnetic field induction at the centre will be

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A circular coil of radius 4 cm and of 20 turns carries a current of 3 amperes. It is placed in a magnetic field of intensity of 0.5 weber/m². The magnetic dipole moment of the coil is

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0.15 ampere-m2
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0.3 ampere-m2
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0.45 ampere-m2
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0.6 ampere-m2

A closed loop PQRS carrying a current is placed in a uniform magnetic field. If the magnetic forces on segment PS, SR and RQ are F₁, F₂ and F₃ respectively and are in the plane of the paper and along the directions shown, the force on the segment QP is
Physics-Moving Charges and Magnetism-83511.png

Physics-Moving Charges and Magnetism-83511.png

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If two streams of protons move parallel to each other in the same direction, then they

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Do not exert any force on each other
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Repel each other
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Attract each other
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Get rotated to be perpendicular to each other

Two parallel wires carrying currents in the same direction attract each other because of

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Potential difference between them
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Mutual inductance between them
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Electric force between them
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Magnetic force between them

A small circular flexible loop of wire of radius r carries a current I. It is placed in a uniform magnetic field B. The tension in the loop will be doubled if

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I is doubled
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B is halved
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r is doubled
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Both B and I are doubled

In a moving coil galvanometer, the deflection of the coil θ is related to the electrical current i by the relation

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The unit of electric current \ ampere\ is the current which when flowing through each of two parallel wires spaced 1 m apart in vaccum and of infinite length will give rise to a force between them equal to

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1 N/m
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2 × 10–7 N/m
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1 × 10–2 N/m
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4π × 10–7 N/m

Four wires each of length 2.0 metres are bent into four loops P, Q, R and S and then suspended into uniform magnetic field. Same current is passed in each loop. Which statement is correct
Physics-Moving Charges and Magnetism-83527.png

Physics-Moving Charges and Magnetism-83527.png

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Couple on loop P will be the highest
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Couple on loop Q will be the highest
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Couple on loop R will be the highest
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Couple on loop S will be the highest

The coil of a galvanometer consists of 100 turns and effective area of 1 square cm. The restoring couple is 10^–8 N-m/radian. The magnetic field between the pole pieces is 5 T. The current sensitivity of this galvanometer will be

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5 × 104 rad/μamp
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5 × 10–6 per amp
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2 × 10–7 per amp
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5 rad /μ amp

Three long, straight and parallel wires carrying current are arranged as shown in the figure. The wire C which carries a current of 5.0 amp is so placed that it experiences no force. The distance of wire C from wire D is then
Physics-Moving Charges and Magnetism-83532.png

Physics-Moving Charges and Magnetism-83532.png

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9 cm
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7 cm
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5 cm
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3 cm

A power line lies along the east-west direction and carries a current of 10 ampere. The force per metre due to the earth\'s magnetic field of 10^–4 tesla is

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10–5 N
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10–4 N
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10–3 N
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10–2 N

A straight wire of length 0.5 metre and carrying a current of 1.2 ampere is placed in a uniform magnetic field of induction 2 tesla. The magnetic field is perpendicular to the length of the wire. The force on the wire is

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2.4 N
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1.2 N
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3.0 N
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2.0 N

Two parallel wires in free space are 10 cm apart and each carries a current of 10 A in the same direction. The force one wire exerts on the other per metre of length is

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2 × 10–4 N, attractive
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2 × 10–4 N, repulsive
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2 × 10–7 N, attractive
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2 × 10–7 N, repulsive

What is the net force on the square coil
Physics-Moving Charges and Magnetism-83537.png

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25 × 10–7 N moving towards wire
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25 × 10–7 N moving away form wire
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35 × 10–7 N moving towards wire
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35 × 10–7 N moving away from wire

In order to increase the sensitivity of a moving coil galvanometer, one should decrease

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The strength of its magnet
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The torsional constant of its suspension
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The number of turns in its coil
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The area of its coil

A circular loop has a radius of 5 cm and it is carrying a current of 0.1 amp. Its magnetic moment is

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1.32 × 10–4 amp-m2
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2.62 × 10–4 amp-m2
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5.25 × 10–4 amp-m2
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7.85 × 10–4 amp-m2

Physics-Moving Charges and Magnetism-83541.png

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Zero
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IBL
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2 IBL
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1/2 IBL

A circular coil having N turns is made from a wire of length L meter. If a current I ampere is passed through it and is placed in a magnetic field of B tesla, the maximum torque on it is

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Directly proportional to N
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Inversely proportional to N
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Inversely proportional to N2
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Independent of N

A small cylindrical soft iron piece is kept in a galvanometer so that

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A radial uniform magnetic field is produced
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A uniform magnetic field is produced
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There is a steady deflection of the coil
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All of the above

The wire loop formed by joining two semicircular sections of radii R₁ and R₂ and center C, carries a current /as shown in the figure. The magnetic field at C has a magnitude
Physics-Moving Charges and Magnetism-83544.png

Physics-Moving Charges and Magnetism-83544.png

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An infinitely long hollow conducting cylinder with inner radius R/2 and outer radius R carries a uniform current density along its length. The magnitude of the magnetic field, I B as a function of the radial distance r from the axis is best represented by

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A charge Q is uniformly distributed over the surface of non-conducting disc of radius R. The disc rotates about an axis perpendicular to its plane and passing through its centre with an angular velocity ω. As a result of this rotation, a magnetic field of induction B is obtained at the centre of the disc. If we keep both the amount of charge placed on the disc and its angular velocity to be constant and vary the radius of the disc, then the variation of the magnetic induction at the centre of the disc will be represented by the figure.

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A long insulated copper wire is closely wound as a spiral of N turns. The spiral has inner radius a and outer radius b. The spiral lies in the X–Y plane and a steady current I flows through the wire. The Z-component of the magnetic field at the centre of the spiral is
Physics-Moving Charges and Magnetism-83560.png

Physics-Moving Charges and Magnetism-83560.png

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A charge q coulomb moves in a circle at n revolutions per second and the radius of the circle is r metre. Then, the magnetic field at the centre of the circle is

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Biot-Savart's law may be represented in vector form as

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The magnetic field at the point of intersection of diagonals of a square wire loop of side L carrying a current I is

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Current through ABC and A'B'C' is I. What is the magnetic field at P ? BP = PB' = r (Here C'B' PBC are collinear)
Physics-Moving Charges and Magnetism-83581.png

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zero

A part of a long wire carrying a current i is bent into a circle of radius r as shown in figure. The net magnetic field at the centre O of the circular loop is
Physics-Moving Charges and Magnetism-83586.png

Physics-Moving Charges and Magnetism-83586.png

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A current I enters a circular coil of radius R, branches into two parts and then recombines as shown in the circuit diagram. The resultant magnetic field at the centre of the coil is
Physics-Moving Charges and Magnetism-83592.png

Physics-Moving Charges and Magnetism-83592.png

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zero
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Current I is flowing in conductor shaped as shown in the figure. The radius of the curved part is r and the length of straight portion is very large. The value of the magnetic field at the centre O will be
Physics-Moving Charges and Magnetism-83598.png

Physics-Moving Charges and Magnetism-83598.png

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A straight conductor of length l carrying a current I, is bent in the form of a semicircle. The magnetic field (in tesla) at the centre of the semicircle is

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In the figure shown, the magnetic field induction at the point 0 will be
Physics-Moving Charges and Magnetism-83609.png

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The magnetic field at the point of intersection of diagonals of a square loop of side L carrying a current I is

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The figure shows the cross-section of a long cylindrical conductor of radius a carrying a uniformly distributed current i. The magnetic field due to current at P is

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μ0ir / (2πa2)
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μ0ir2 / (2πa)
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μ0ia / (2πr2)
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μ0ia2 / (πr2)

If the radius of the dees of cyclotron is r, then the kinetic energy of a proton of mass m accelerated by the cyclotron at an oscillating frequency v is

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4 π2 m2 v2 r2
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4 π2 m v2 r2
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2 π2 m v2 r2
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π2 m v2 r2
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π2 m2 v2 r2

Which of the field pattern given in the figure is valid for electric field as well as for magnetic field?

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A thin circular disk of radius R is uniformly charged with density σ > 0 per unit area. The disk rotates about its axis with a uniform angular speed ω. The magnetic moment of the disk is

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2πR4 σω
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πR4 σω
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0%

Physics-Moving Charges and Magnetism-83628.png

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1

Two particles of equal charges after being accelerated through the same potential difference enter a uniform transverse magnetic field and describe circular path of radii R₁ and R₂, respectively. Then the ratio of their masses (M₁/M₂) is

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A charged particle is moving in a magnetic field of strength B perpendicular to the direction of the field. if q and m denote the charge and mass of the particle respectively, then the frequency of rotation of the particle is

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A charge particle of mass m and charge q enters a region of uniform magnetic field B perpendicular of its velocity v. The particle initially at rest was accelerated by a potential difference V (volts) before it entered the region of magnetic field. What is the diameter of the circular path followed by the charged particle in the region of magnetic field ?

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An electron having mass (9.1 × 10^-31 kg) and charge (1.6 × 10^-19 C) moves in a circular path of radius 0.5 m with a velocity 106 m s ^-1 in

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1.13 × 10-5 T
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5.6 × 10-6 T
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2.8 × 10-6 T
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None of these

A thin flexible wire of length L is connected to two adjacent fixed points and carries a current I in the clockwise direction, as shown in the figure. When the system is put in a uniform magnetic field of strength B going into the plane of the paper, the wire takes the shape of a circle. The tension in the wire is
Physics-Moving Charges and Magnetism-83655.png

Physics-Moving Charges and Magnetism-83655.png

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An electron is moving in an orbit of radius R with a time period T as shown in the figure. The magnetic moment produced may be given by
Physics-Moving Charges and Magnetism-83661.png

Physics-Moving Charges and Magnetism-83661.png

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The resultant force on the current loop PQRS due to a long current carrying conductor will be
Physics-Moving Charges and Magnetism-83667.png

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10-4 N
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3.6 × 10-4 N
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1.8 × 10-4 N
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5 × 10-4 N

Three long, straight parallel wires, carrying current, are arranged as shown in figure. The force experienced by a 25 cm length of wire C is
Physics-Moving Charges and Magnetism-83669.png

Physics-Moving Charges and Magnetism-83669.png

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10-3 N
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2.5 × 10-3 N
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zero
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1.5 × 10-3

The figure shows three situations when an electron with velocity v travels through a uniform magnetic field B. In each case, what is the direction of magnetic force on the electron?
Physics-Moving Charges and Magnetism-83671.png

Physics-Moving Charges and Magnetism-83671.png

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+ ve z – axis, – ve x – axis, + ve y – axis
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– ve z-axis, – ve x – axis and zero
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+ ve z – axis, + ve y – axis and zero
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– ve z – axis, + ve y – axis and zero

Physics-Moving Charges and Magnetism-83672.png

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A and B are two conductors carrying a current I in the same direction, x and y are two electron beams moving in the same direction.
Physics-Moving Charges and Magnetism-83678.png

Physics-Moving Charges and Magnetism-83678.png

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There will be attraction between A and B and also x and y.
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There will be repulsion between A and B and also x and y
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There will be attraction between A and B, repulsion between x and y
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There will be repulsion between A and B, attraction between x and y

JEE Questions for Physics Moving Charges And Magnetism Quiz 14 - MCQExams.com

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JEE Questions for Physics Moving Charges And Magnetism Quiz 14 - MCQExams.com

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