Magnetism and electromagnetism

how many type of magnets are there?
1. one
2. two
3. three
4. four
The strongest natural magnet is
1. lodestones magnetite
2. leadstones magnetite
3. both (a) and (b)
4. none of these
The magnetic property in the natural magnet is
1. permanent
2. temperory
3. semi permanent
4. none of these
The magnets available in the shop are basically
1. artificial magnet
2. natural magnet
3. both (a) and (b)
4. none of these
There is an ................ field all around the magnet which attracts magnetic material.
1. invisible
2. visible
3. both (a) and (b)
4. none of these
the ............................. is the region around the magnet where magnetic influence can be felt
1. electromagnetic field
2. magnetic field
3. both (a) and (b)
4. none of these
The symbol of magnetic field is
1. M
2. E
3. B
4. V
Unit of magnetic field is
1. voltage
2. ampere
3. weber
4. tesla
The direction of magnetic field around the magnet can be found by placing a small.............in the magnetic field
1. bulb
2. iron
3. compass
4. needle
...................produce itsown magnetic field
1. mars
2. venus
3. pluto
4. earth
The ................... to the curve at any point give direction to the magnetic field
1. line
2. chord
3. line segment
4. tangent
Outside the magnet the magnetic field lines goes from ..................... direction
1. north to south
2. south to north
3. east to west
4. west to east
............... is the number of magnetic field lines passing through a given area
1. magnetic field
2. electric field
3. electric flux
4. magnetic flux
unit of magnetic flux is
1. tesla
2. watt
3. weber
4. voltage
unit of magnetic flux density is
1. tesla/ $m^{2}$
2. weber/ $m^{2}$
3. newton/ $m^{2}$
4. none of these
Magnetic flux is denoted by
1. $ϕ$
2. $θ$
3. $\in$
4. $∆$
Magnetic lines of force never
1. intersect
2. parallel
3. both
4. none of these
Magnetic field lines will be maximum at the
1. equator
2. centre
3. pole
4. none of these
the direction of magnetic field around a current carrying conductor can be easily understood using the ..................
1. flemings right hand rule
2. right hand thumb rule
3. flemings left hand thumb rule
4. left hand thumb rule
The strength of the magnetic field at a point due to current carrying wire depends on
1. distance of the point from the wire
2. the current in the wire
3. both a and b
4. none of these
H.A.Lorentz found that a charge moving in a magnetic field, in a direction other than the direction of magnetic field, experiences a force. It is called the
1. magnetic force
2. electric force
3. magnetic lorentz force
4. none of these
.......................... discovered that a current carrying conductor also gets deflected when it is placed in a magnetic field.
1. Michael Faraday
2. H.A Lorentz
3. Hans christian oersted
4. none of these
If a current, I is flowing through a conductor of length, L kept perpendicular to the magnetic field B, then the force F experienced by it is given by the equation
1. F=IB/L
2. F=LB/ I
3. F= ILB
4. none of these
The angle of ................ between the current and magnetic field also affects the magnetic force
1. normal
2. incidence
3. reflection
4. none of these
When the conductor is perpendicular to the magnetic field, the force will be.........
1. maximum
2. minimum
3. zero
4. none of these
When conductor is parallel to the magnetic field, the force will be
1. maximum
2. minimum
3. zero
4. none of these
The force is always a ............ quantity
1. scaler
2. vector
3. both
4. none of these
A vector quantity has........
1. only magnitude
2. only direction
3. both magnitude and direction
4. none of these
while stretching the three fingers of left hand in perpendicular
manner the current is denoted by the middle finger of the left hand and the second finger is for direction of the magnetic field, then the thumb of the left hand denotes the direction of the force or movement of the conductor. which law is this
1. flemings left hand rule
2. flemings right hand rule
3. both
4. none of these
A conductor of length 50 cm carrying a current of 5 A is placed perpendicular to a magnetic field of induction 2×10–3 T. Find the force on the conductor
1. 4 $\times 10^{- 3}$
2. 5 $\times 10^{- 3}$
3. 7 $\times 10^{- 3}$
4. 2 $\times 10^{- 3}$
After................. experiment the electricity and magnetism were united and became a single subject called ‘Electromagnetism
1. freud's
2. Oersted's
3. charles darvin
4. none of these
In the twentieth century, we understood that the magnetic property arises due to the motion of ............... in the lodestone.
1. neutrons
2. protons
3. electrons
4. none of these
An ................ is a device which converts electrical energy into mechanical energy
1. electric motor
2. generator
3. battery
4. switch
In electric motor to change the direction of the current, a small device called .............. is used.
1. magnet
2. coil
3. carbon brush
4. split ring commutator
The speed of rotation of coil in electric motor can be increased by:
1. increasing the strength of coil in the current
2. increasing the number of turns in the coil
3. none of these
4. both of them
The possibility of producing an e.m.f across the conductor when the magnetic flux linked with the conductor is changed. it is explained by
1. freud
2. oersted
3. faraday
4. charles
The phenomenon of producing an induced emf due to change in the magnetic flux linked with a closed circuit is known as .
1. electromagnet
2. electromagnetic induction
3. magnetization
4. none of these
The direction of the induced current was given by ......... law
1. Lenz’s
2. freud's
3. fleming's
4. none of these
The direction of induced current can also be given by another rule called
1. thumb rule
2. Fleming’s left Hand Rule
3. Fleming’s Right Hand Rule
4. none of these
Fleming’s Right hand rule is also called ..............
1. 'generator rule'
2. electrolysis
3. electromagnetic induction
4. none o fthese
rotating rectangular coil in AC generator is called
1. brush
2. armature
3. slip ring
4. none of these
When the coil is rotated in AC generator the ............... linked with the coil changes.
1. electric flux
2. voltage
3. magnetic flux
4. current
To get a direct current (DC), in an AC generator ........... type commutator must be used.
1. split ring
2. carbon brushes
3. load
4. none of these
................. is a device used for converting low voltage into high voltage and high voltage into low voltage.
1. dc generator
2. speaker
3. transformer
4. ac generator
Transformer works on the principle of ........................
1. magnetisation
2. electromagnetic induction
3. electric flux
4. none of these
The transformer used to change a low alternativing voltage to a high alternating voltage is called a .............. transformer
1. step up
2. step down
3. both
4. none of these
In a step up transformer, the number of turns in the secondary coil is.......... than the number of turns in the primary coil.
1. less
2. more
3. equal
4. none of these
A transformer cannot be used with the direct current (DC) source because, current in the primary coil is............
1. constant
2. continious
3. alternating
4. none of these
...................... is a method by which an object is suspended with no support other than magnetic fields
1. electromatic induction
2. Magnetic levitation
3. both (a) and (b)
4. none of these
„™ Two parallel wires carrying current in the opposite directions .......... each other
1. repel
2. attract
3. both
4. none of these

Magnetism and electromagnetism

Quiz