A magnetic field exists around
(a) iron
(b) copper
(c) aluminium
(d) moving charges

1 Answer

Answer :

(d) moving charges

Related questions

Description : The space around the charge within which other charges are influenced by it is called: (a) Electric field (b) Magnetic field (c) Electric flux (d) Electric intensity

Last Answer : a) Electric field

Description : The electric field exist around: (a) Charges (b) On the left side (c) At the –ve charge (d) At the +ve charge

Last Answer : (a) Charges

Description : The induced current can be increased by: a. Using strong magnetic field b. moving loop faster c. Replacing loop by coil d. all of above

Last Answer : d. all of above

Description : If velocity of a conductor moving through a magnetic field ‘B’ is made zero, then Motional emf will be: a. –VBL b. –V/BL c. – BL/V d. zero

Last Answer : a. –VBL

Description : A proton and a deuteron have same kinetic energies while moving in a perpendicular magnetic field. The following gives the ratio of radii of their circular paths a) √2 : 1 b) 1: √2 c) 1:4 d) 1:1

Last Answer : b) 1: √2

Description : Work done by a uniform magnetic field in moving a charged particle in a circular path is a) qvB sin θ b) mg sin θ c) zero d) mg cos θ

Last Answer : Zero

Description : The pole faces of U-shaped magnet in a moving coil galvanometer are made concave to a) decrease the strength of magnetic field b) create a non-uniform magnetic field c) make the magnetic field radial d) All of these

Last Answer : c) make the magnetic field radial

Description : ___________ is not affected by a magnetic field a) Change in magnetic flux b) a moving electron c) a stationary proton d) current flowing in a conductor

Last Answer : c) a stationary proton

Description : When an iron piece is placed in a magnetic field (a) the magnetic lines of force will bend away from their usual paths in order to go away from the piece (b) the magnetic lines of force will bend ... to pass through the piece (c) the magnetic field will not be affected (d) the iron piece will break

Last Answer : (b) the magnetic lines of force will bend away from their usual paths in order to pass through the piece

Description : The practical application of electrostatic is: (a) Photocopier (b) X-rays machines (c) Laser (d) All of above 42. The electric field lines emerge from the charges in: (a) Three dimensions (b) Two dimensions (c) One dimension (d) All of above

Last Answer : (a) Photocopier

Description : A proton is moving in a uniform magnetic field B in a circular path of radius a in a direction perpendicular to Z- axis along which field B exists. Ca

Last Answer : A proton is moving in a uniform magnetic field B in a circular path of radius a in a direction perpendicular to Z- ... 2)a` C. `a^(2) eB` D. `aeB`

Description : A proton of mass m and charge q is moving in a plane with kinetic energy E. if there exists a uniform magnetic field B, perpendicular to the plane mot

Last Answer : A proton of mass m and charge q is moving in a plane with kinetic energy E. if there exists a uniform magnetic ... Em))/(2qB)` D. `(sqrt(2Eq))/(qB)`

Description : The most suitable metal for making permanent magnet is a) Iron b) Steel c) Silver d) Copper

Last Answer : a) Iron

Description : Which one of the following materials is useful for making bulb filaments? a. aluminum b. Iron c. Copper d. Tungsten

Last Answer : a. aluminum

Description : Which one is the best material for making connecting wires? a. Iron b. Tungsten c. Silver d. Copper

Last Answer : d. Copper

Description : A conductor of length L has current I passing through it, when it is placed parallel to a magnetic field. The force experienced by the conductor will be (a) zero (b) BLI (c) B2LI (d) BLI2

Last Answer : (a) zero

Description : The left hand rule correlates to (a) current, induced e.m.f. and direction of force on a conductor (b) magnetic field, electric field and direction of force on a conductor (c) self induction, ... and direction of force on a conductor (d) current, magnetic field and direction of force on a conductor

Last Answer : (d) current, magnetic field and direction of force on a conductor

Description : Fleming's left hand rule is used to find (a) direction of magnetic field due to current carrying conductor (b) direction of flux in a solenoid (c) direction of force on a current carrying conductor in a magnetic field (d) polarity of a magnetic pole

Last Answer : (c) direction of force on a current carrying conductor in a magnetic field

Description : A material which is slightly repelled by a magnetic field is known as (a) ferromagnetic material (b) diamagnetic material (c) paramagnetic material (d) conducting material

Last Answer : (b) diamagnetic material

Description : Which of the following is a vector quantity ? (a) Relative permeability (b) Magnetic field intensity (c) Flux density (d) Magnetic potential

Last Answer : (b) Magnetic field intensity

Description : The windings of the electromagnetic are usually called: a. Magnetic coils b. Field coil c. Electric coil d. simple coil

Last Answer : c. Electric coil

Description : The induced emf in a coil depends upon: a. Strength of magnetic field b. Resistance of the coil c. area of the coil d. All of them

Last Answer : d. All of them

Description : In motor a permanent magnet provides: a. Electric field b. electric flux c. magnetic field d. gravitational field

Last Answer : d. gravitational field

Description : A magnetic field acts on a charged particles so as to change its: a. speed b. energy c. direction of motion d. all of these

Last Answer : Only direction of motion will change ...it means velocity will change but speed same

Description : If magnetic field is doubled then magnetic energy density becomes: a. Four times b. Two times c. Three times d. Six times

Last Answer : c. Three times

Description : Electric current produces magnetic field was suggested by: a. Faraday b. Lenz c. Ohm d. Oerested

Last Answer : c. Ohm

Description : A wire loop is moved parallel to a uniform magnetic field. The induced emf in the loop: a. depends on the shape b. depends on area c. depends on nature of loop d. zero

Last Answer : d. zero

Description : When a uniform magnetic field B is applied to a current carrying coil, the coil will rotate in such a manner that its plane a) becomes parallel to B b) becomes anti-parallel to B c) makes an angle of 600 with B d) becomes perpendicular to B

Last Answer : d) becomes perpendicular to B

Description : The magnetic flux φB through a plane element of area A⃗ in a uniform magnetic field B⃗⃗ is minimum at a) θ = 900 b) θ = 00 c) θ = 1800 d) None of these

Last Answer : a) θ = 900

Description : An α particle moves perpendicular to a constant magnetic field of strength 1.2 T in a circular path of radius 0.7 m. The speed of α particle in ms-1 is ______________ a) 2.7 × 107 b) 2.6 × 107 c) 3.2 × 107 d) 2.0 × 107

Last Answer : a) 2.7 × 107

Description : A solenoid has n turns and length l. If length is reduced to l/2 and turns are doubled then magnetic field B produced by it becomes equal to a) 2B b) 4B c) 1/2 B d) None of these

Last Answer : a) 2B

Description : A current of 5.8 A flows through a 0.25 m long straight conductor which is kept perpendicular in a region of uniform magnetic field of 3.7 T . The force on conductor is a) 5.4 N b) 2.4 N c) 3.4 N d) 6.4 N

Last Answer : a) 5.4 N

Description : The magnetic field is _________ inside a solenoid a) Zero b) uniform c) non-uniform d) infinite

Last Answer : b) uniform

Description : A proton and a α particle enter a region having a perpendicular uniform magnetic field. The ratio of time period of proton (τp) to time period of α particle (τα) is a) 1:4 b) 4:1 c) 2:1 d) 1:2

Last Answer : d) 1:2

Description : A proton having mass m and charge q is projected into a region having a perpendicular magnetic field. The angle of deviation of proton when it comes out of the region with mv √2 qB ⁄ is a) π/3 b) π/4 c) π/6 d) 2 π/3

Last Answer : b) π/4

Description : ___________ remain undeflected in a magnetic field a) β particles b) α particles c) γ rays d) Proton beams

Last Answer : c) γ rays

Description : A magnetic screw placed in a non-uniform magnetic field experiences a) force and torque b) only torque c) only force d) None of these

Last Answer : a) force and torque

Description : An electron moves with a velocity of 2 × 106 ms-1 in the direction of a uniform magnetic field of 0.8 Tesla. The force on electron is a) 8 N b) 2 N c) 4 N d) Zero

Last Answer : d) Zero

Description : Which of the following quantities change when a proton moves at right angles to a magnetic field? a) Momentum b) Energy c) Speed d) All of these

Last Answer : a) Momentum

Description : A proton moves in a uniform magnetic field in a circular path of radius R. If the energy of proton is doubled then the new radius becomes a) R √2 b) 2R c) R 2 d) √2 R

Last Answer : d) √2 R

Description : An electron and a neutron enter a magnetic field with the same velocity. Ratio of electron to neutron’s acceleration is a) mn me b) √ mn me c) √ me mn d) me

Last Answer : a) mn me

Description : When the field is strong, the lines of force are: (a) Closer (b) Parallel (c) Farther (d) All of above 45. The electric lines of force determine the strength of an: (a) Gravitational field (b) Constant field (c) Magnetic field (d) Electric field

Last Answer : d) Electric field

Description : The conventional current is due to the flow of a. atoms and molecules b. positive charges c. negative charges d. both b and c

Last Answer : b. positive charges

Description : In liquids and gases the current is due to the motion a. negative charges b. positive charges c. both negative and positive charges d. neutral particles

Last Answer : c. both negative and positive charges

Description : In case of two identical charges placed at certain distance, the electric lines of force are: (a) Curved (b) Straight lines (c) Both (a) and (b) (d) None of these

Last Answer : a) Curved

Description : The electric force between two charges placed in air is 2 Newton. When placed in a medium of ∈r = 80, the force reduced to: (a) 0.029 N (b) 0.025 N (c) 0.03 N (d) 0.04 N

Last Answer : (b) 0.025 N

Description : Which of the following statement is correct: (a) Similar charges attract each other (b) Similar charges attract and repel each other (c) Similar charges repel each other (d) Similar charges neither attract nor repel 9. Metals are good conductors of electricity because they have:

Last Answer : (c) Similar charges repel each other

Description : When the medium is insulator the electrostatic force between the charges is: (a) Decreased (b) Zero (c) Increased (d) None of above

Last Answer : (a) Decreased

Description : The branch of physics which deals with the charges at rest: (a) Current electricity (b) Electromagnetism (c) Electrostatics (d) Nuclear physics

Last Answer : (c) Electrostatics

Last Answer : A magnetic field exists around moving charges.