Physics M.C.Q (1 Marks)

Assertion : A direct current flows through a metallic rod, produced magnetic field only outside the rod.
Reason : There is no flow of charge carriers inside the rod.

Assertion : If two long wires, hanging freely are connected to a battery in series, they come closer to each other.
Reason : Force of attraction acts between the two wires carrying current.

Assertion : If a charged particle is moving on 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.

Assertion : The magnetic filed 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 within it is uniform.

Assertion : A loosely round helix made of stiff wire is suspended vertically with the lower end just touching a dish of mercury. When a current is passed through the wire, the helical wire executes oscillatory motion with the lower end jumping out of and inside of mercury.
Reason : When electric current is passed through helix, a magnetic field is produced both inside and outside the helix.

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.

Assertion : An electron and 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.

A uniform conducting wire ABC has a mass of 10g. A current of 2A flows through it. The wire is kept in a uniform magnetic field B = 2T. The acceleration of the wire will be

Assertion : The energy of charged particle moving in a uniform magnetic field does not change.
Reason : Work done by magnetic field on the charge is zero.

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.

Assertion : The coil is bound over the metallic frame in moving coil galvanometer.
Reason : The metallic frame help in making steady deflection without any oscillation.

Assertion : The ion cannot move with a speed beyond a certain limit in a cyclotron.
Reason : As velocity increases time taken by ion increases.

Assertion : Cyclotron is a device which is used to accelerate the positive ion.
Reason : Cyclotron frequency depends upon the velocity.

Assertion : Magnetic field interacts with a moving charge and not with a stationary charge.
Reason : A moving charge produces a magnetic field.

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.

Assertion : Free electron always keep on moving in a conductor even then no magnetic force act on them in magnetic field unless a current is passed through it.
Reason : The average velocity of free electron is zero.

If current flowing through shell of previous objective is equal to i, then energy density at a point distance 2R from axis of the shell varies according to the graph

If induction of magnetic field at a point is B and energy density is U then which of the following graphs is correct

The (? – ?) graph for a coil is

A particle of charge q and mass m is moving along the x -axis with a velocity v and enters a region of electric field E and magnetic field B as shown in figure below for which figure the net force on the charge may be zero

The correct curve between the magnetic induction (B) along the axis of a long solenoid due to current flow i in it and distance x from one end is

A long thin hollow metallic cylinder of radius 'R' has a current i ampere. The magnetic induction 'B'-away from the axis at a distance r from the axis varies as shown in

Which of the following graphs shows the variation of magnetic induction B with distance r from a long wire carrying current

Two long parallel wires are at a distance 2d apart. They carry steady equal currents flowing out of the plane of the paper, as shown. The variation of the magnetic field B along the line XX’ is given by 

The magnetic field due to a straight conductor of uniform cross section of radius a and carrying a steady current is represented by 

An electron is moving along the positive X-axis. You want to apply a magnetic field for a short time so that the electron may reverse its direction and move parallel to the negative X-axis. This can be done by applying the magnetic field along

AB and CD are long straight conductor, distance d apart, carrying a current I. The magnetic field at the midpoint of BC is

A proton accelerated by a potential difference 500 KV moves though a transverse magnetic field of 0.51T as shown in figure. The angle θ through which the proton deviates from the initial direction of its motion is

In the given figure net magnetic field at O will be

A horizontal rod of mass 10 gm and length 10 cm is placed on a smooth plane inclined at an angle of 60° with the horizontal, with the length of the rod parallel to the edge of the inclined plane. A uniform magnetic field of induction B is applied vertically downwards. If the current through the rod is 1.73 ampere, then the value of B for which the rod remains stationary on the inclined plane is

A particle of mass m and charge q moves with a constant velocity v along the positive x direction. It enters a region containing a uniform magnetic field B directed along the negative z direction, extending from x = a to x = b. The minimum value of v required so that the particle can just enter the region x > b is

Same current i = 2A is flowing in a wire frame as shown in figure. The frame is a combination of two equilateral triangles ACD and CDE of side 1m. It is placed in uniform magnetic field B = 4T acting perpendicular to the plane of frame. The magnitude of magnetic force acting on the frame is

Two thick wires and two thin wires, all of the same materials and same length form a square in the three different ways P, Q and R as shown in fig with current connection shown, the magnetic field at the centre of the square is zero in cases

A long wire AB is placed on a table. Another wire PQ of mass 1.0 g and length 50 cm is set to slide on two rails PS and QR. A current of 50A is passed through the wires. At what distance above AB, will the wire PQ be in equilibrium

Two infinite length wires carries currents 8A and 6A respectively and placed along X and Y-axis. Magnetic field at a point P(0, 0, d)m will be

The ratio of the magnetic field at the centre of a current carrying circular wire and the magnetic field at the centre of a square coil made from the same length of wire will be

What will be the resultant magnetic field at origin due to four infinite length wires. If each wire produces magnetic field 'B' at origin

A ring of radius R, made of an insulating material carries a charge Q uniformly distributed on it. If the ring rotates about the axis passing through its centre and normal to plane of the ring with constant angular speed ω, then the magnitude of the magnetic moment of the ring is

Two particles each of mass m and charge q are attached to the two ends of a light rigid rod of length 2R. The rod is rotated at constant angular speed about a perpendicular axis passing through its centre. The ratio of the magnitudes of the magnetic moment of the system and its angular momentum about the centre of the rod is

Two insulated rings, one of slightly smaller diameter than the other are suspended along their common diameter as shown. Initially the planes of the rings are mutually perpendicular. When a steady current is set up in each of them

A current carrying loop is placed in a uniform magnetic field in four different orientations, I,II, III & IV arrange them in the decreasing order of potential Energy
(a)(b) (c) (d)

A conducting loop carrying a current I is placed in a uniform magnetic field pointing into the plane of the paper as shown. The loop will have a tendency to

Two very thin metallic wires placed along X and Y-axis carry equal currents as shown here. AB and CD are lines at 45° with the axes with origin of axes at O. The magnetic field will be zero on the line

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

A particle of charge q and mass m moves in a circular orbit of radius r with angular speed ω. The ratio of the magnitude of its magnetic moment to that of its angular momentum depends on

A thin circular wire carrying a current I has a magnetic moment M. The shape of the wire is changed to a square and it carries the same current. It will have a magnetic moment

A wire of length L metre carrying a current of I ampere is bent in the form of a circle. Its magnitude of magnetic moment will be

Two long wires are hanging freely. They are joined first in parallel and then in series and then are connected with a battery. In both cases, which type of force acts between the two wires

An ionized gas contains both positive and negative ions. If it is subjected simultaneously to an electric field along the +x direction and a magnetic field along the +z direction, then

An infinitely long, straight conductor AB is fixed and a current is passed through it. Another movable straight wire CD of finite length and carrying current is held perpendicular to it and released. Neglect weight of the wire

A non-planar loop of conducting wire carrying a current I is placed as shown in the figure. Each of the straight sections of the loop is of length 2a. The magnetic field due to this loop at the point P (a,0,a) points in the direction

A coil having N turns is wound tightly in the form of a spiral with inner and outer radii a and b respectively. When a current I passes through the coil, the magnetic field at the centre is

The field normal to the plane of a wire of n turns and radius r which carries a current i is measured on the axis of the coil at a small distance h from the centre of the coil. This is smaller than the field at the centre by the fraction

The magnetic field at the centre of a circular coil of radius r is π times that due to a long straight wire at a distance r from it, for equal currents. Figure here shows three cases : in all cases the circular part has radius r and straight ones are infinitely long. For same current the B field at the centre P in cases 1, 2, 3 have the ratio

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

In ballistic galvanometer, the frame on which the coil is wound is non-metallic to

Current i is carried in a wire of length L. If the wire is turned into a circular coil, the maximum magnitude of torque in a given magnetic field B will be

A beam of electrons and protons move parallel to each other in the same direction, then they

A one metre 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

The resultant magnetic moment of neon atom will be

If the current is doubled, the deflection is also doubled in

Two long straight parallel conductors separated by a distance of 0.5m carry currents of 5A and 8A in the same direction. The force per unit length experienced by each other is

Two galvanometers A and B require 3mA and 5mA respectively to produce the same deflection of 10 divisions. Then

A circular loop carrying a current is replaced by an equivalent magnetic dipole. A point on the axis of the loop is

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

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

If a wire of length 1 meter placed in uniform magnetic field 1.5 Tesla at angle 30° with magnetic field. The current in a wire 10 amp. Then force on a wire will be

What is shape of magnet in moving coil galvanometer to make the radial magnetic field

A stream of electrons is projected horizontally to the right. A straight conductor carrying a current is supported parallel to electron stream and above it. If the current in the conductor is from left to right then what will be the effect on electron stream

The magnetic moment of a circular coil carrying current is

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

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

What is the net force on the square coil

If m is magnetic moment and B is the magnetic field, then the torque is given by

Magnetic dipole moment of a rectangular loop is

Two parallel beams of electrons moving in the same direction produce a mutual force

There long straight wires A, B and C are carrying current as shown figure. Then the resultant force on B is directed .....

A circular coil of diameter 7cm has 24 turns of wire carrying current of 0.75A. The magnetic moment of the coil is

The current sensitivity of a moving coil galvanometer can be increased by

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

A small coil of N turns has area A and a current I flows through it. The magnetic dipole moment of this coil will be

A coil carrying electric current is placed in uniform magnetic field, then

A vertical wire carrying a current in the upward direction is placed in horizontal magnetic field directed towards north. The wire will experience a force directed towards

Three long, straight and parallel wires carrying currents 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

A triangular loop of side l carries a current I. It is placed in a magnetic field B such that the plane of the loop is in the direction of B. The torque on the loop is

A current carrying small loop behaves like a small magnet. If A be its area and M its magnetic moment, the current in the loop will be

If a current is passed in a spring, it

A rectangular coil 20 cm × 20 cm has 100 turns and carries a current of 1 A. It is placed in a uniform magnetic field B = 0.5 T with the direction of magnetic field parallel to the plane of the coil. The magnitude of the torque required to hold this coil in this position is

A conductor in the form of a right angle ABC with AB = 3 cm and BC = 4 cm carries a current of 10 A. There is a uniform magnetic field of 5 T perpendicular to the plane of the conductor. The force on the conductor will be

A current of 5 ampere is flowing in a wire of length 1.5 metres. A force of 7.5 N acts on it when it is placed in a uniform magnetic field of 2 Tesla. The angle between the magnetic field and the direction of the current is

Three long, straight and parallel wires carrying currents are arranged as shown in figure. The force experienced by 10 cm length of wire Q is

Two parallel conductors A and B of equal lengths carry currents I and 10 I, respectively, in the same direction. Then

A metallic loop is placed in a magnetic field. If a current is passed through it, then

The sensitiveness of a moving coil galvanometer can be increased by decreasing

The pole pieces of the magnet used in a pivoted coil galvanometer are

A current carrying loop is free to turn in a uniform magnetic field. The loop will then come into equilibrium when its plane is inclined at

A current carrying circular loop is freely suspended by a long thread. The plane of the loop will point in the direction

A current carrying rectangular coil is placed in a uniform magnetic field. In which orientation, the coil will not tend to rotate

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

An electron moves with a constant speed v along a circle of radius r. Its magnetic moment will be (e is the electron's charge) 

A current of 10 ampere is flowing in a wire of length 1.5 m. A force of 15 N acts on it when it is placed in a uniform magnetic field of 2 tesla. The angle between the magnetic field and the direction of the current is

A charged particle of mass m and charge q travels on 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

A moving coil galvanometer has N number of turns in a coil of effective area A, it carries a current I. The magnetic field B is radial. The torque acting on the coil is

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

A moving coil sensitive galvanometer gives at once much more deflection. To control its speed of deflection

The deflection in a moving coil galvanometer is

To make the field radial in a moving coil galvanometer

The radius of a circular loop is r and a current i is flowing in it. The equivalent magnetic moment will be

3 A 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 the direction of the field. It experiences a force of magnitude

Two free parallel wires carrying currents in opposite direction

A rectangular loop carrying a current i is situated near a long straight wire such that the wire is parallel to the one of the sides of the loop and is in the plane of the loop. If a steady current I is established in wire as shown in figure, the loop will

Through two parallel wires A and B, 10 and 2 ampere of currents are passed respectively in opposite direction. If the wire A is infinitely long and the length of the wire B is 2 m, the force on the conductor B, which is situated at 10 cm distance from A will be

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

Two parallel wires are carrying electric currents of equal magnitude and in the same direction. They exert

Two long and parallel wires are at a distance of 0.1 m and a current of 5 A is flowing in each of these wires. The force per unit length due to these wires will be

The electron 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

A very high magnetic field is applied to a stationary charge. Then the charge experiences

An electron is projected along the axis of a circular conductor carrying some current. Electron will experience force

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

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

In the given figure, the electron enters into the magnetic field. It deflects in ...... direction

The cyclotron frequency of an electron grating in a magnetic field of 1 T is approximately

An electron is travelling along the x-direction. It encounters a magnetic field in the y-direction. Its subsequent motion will be

Two ions having masses in the ratio 1 : 1 and charges 1 : 2 are projected into uniform magnetic field perpendicular to the field with speeds in the ratio 2 : 3. The ratio of the radii of circular paths along which the two particles move is

A charged particle is released from rest in a region of steady uniform electric and magnetic fields which are parallel to each other the particle will move in a

An electron enters a region where electrostatic field is 20N/C and magnetic field is 5T. If electron passes undeflected through the region, then velocity of electron will be

Which particles will have minimum frequency of revolution when projected with the same velocity perpendicular to a magnetic field

If cathode rays are projected at right angles to a magnetic field, their trajectory is

When a charged particle enters a uniform magnetic field its kinetic energy

Motion of a moving electron is not affected by

An α particle and a proton travel with same velocity in a magnetic field perpendicular to the direction of their velocities, find the ratio of the radii of their circular path

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

Cyclotron is used to accelerate

The radius of circular path of an electron when subjected to a perpendicular magnetic field is

An electron moving towards the east enters a magnetic field directed towards the north. The force on the electron will be directed

A particle of mass m and charge q enters a magnetic field B perpendicularly with a velocity v, The radius of the circular path described by it will be

If an electron enters a magnetic field with its velocity pointing in the same direction as the magnetic field, then

An electron of mass m and charge q is travelling with a speed v along a circular path of radius r at right angles to a uniform of magnetic field B. If speed of the electron is doubled and the magnetic field is halved, then resulting path would have a radius of

A charge of 1C is moving in a magnetic field of 0.5Tesla with a velocity of 10m/sec Perpendicular to the field. Force experienced is

An electron is travelling in east direction and a magnetic field is applied in upward direction then electron will deflect in

A charge q is moving in a magnetic field then the magnetic force does not depend upon

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

In a cyclotron, the angular frequency of a charged particle is independent of

A particle is moving in a uniform magnetic field, then

A particle moving in a magnetic field increases its velocity, then its radius of the circle

A positively charged particle moving due east enters a region of uniform magnetic field directed vertically upwards. The particle will

An electron and a proton with equal momentum enter perpendicularly into a uniform magnetic field, then

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

An electron enters a region where magnetic (B) and electric (E) fields are mutually perpendicular to one another, then

A charge moves in a circle perpendicular to a magnetic field. The time period of revolution is independent of

When a magnetic field is applied in a direction perpendicular to the direction of cathode rays, then their

A moving charge will gain energy due to the application of

An electron is moving along positive x-axis. To get it moving on an anticlockwise circular path in x-y plane, a magnetic filed is applied

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

An electron and a proton enter a magnetic field perpendicularly. Both have same kinetic energy. Which of the following is true

A charged particle is moving with velocity v in a magnetic field of induction B. The force on the particle will be maximum when

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

A current carrying long solenoid is placed on the ground with its axis vertical. A proton is falling along the axis of the solenoid with a velocity v. When the proton enters into the solenoid, it will

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

An electron enters a magnetic field whose direction is perpendicular to the velocity of the electron. Then

n electron is moving on a circular path of radius r with speed v in a transverse magnetic field B. e/m for it will be 

A charge +Q is moving upwards vertically. It enters a magnetic field directed to the north. The force on the charge will be towards

The path executed by a charged particle whose motion is perpendicular to magnetic field i

A proton and an electron both moving with the same velocity v enter into a region of magnetic field directed perpendicular to the velocity of the particles. They will now move in circular orbits such that

A proton (or charged particle) moving with velocity v is acted upon by electric field E and magnetic field B. The proton will move undeflected if

A 2 MeV proton is moving perpendicular to a uniform magnetic field of 2.5 tesla. The force on the proton is

A proton is moving along Z-axis in a magnetic field. The magnetic field is along X-axis. The proton will experience a force along

Which of the following statement is true

A magnetic field

An electron is travelling horizontally towards east. A magnetic field in vertically downward direction exerts a force on the electron along

If a proton is projected in a direction perpendicular to a uniform magnetic field with velocity v and an electron is projected along the lines of force, what will happen to proton and electron

A uniform magnetic field acts at right angles to the direction of motion of electrons. As a result, the electron moves in a circular path of radius 2 cm. If the speed of the electrons is doubled, then the radius of the circular path will be