Magnetic effects of Electric Current

A device for producing electric current is
1. galvanometer
2. electric motor
3. electric generator
4. table fan
Which of the following property of a proton can change when it moves freely in a magnetic field?
1. momentum
2. velocity
3. mass
4. speed
What is the frequency of electricity generated by direct current?
1. zero
2. 220 Hz
3. infinity
4. 50Hz
The most suitable material for making a permanent magnet from the following is ?
1. copper
2. aluminium
3. alnico
4. soft iron
The scientist who discovered the magnetic effects of electric current is
1. Faraday
2. Ampere
3. Oersted
4. Tesla
The diection of field lines inside the magnet is
1. From north pole to south pole
2. From south pole to north pole
3. There are no field lines inside a magnet
4. Towards the south pole
The direction of magnetic field lines outside a magnet is
1. towards north pole
2. away from south pole
3. from south poleto north pole
4. from north pole to south pole
The nature of magnetic field line when it passes through the centre if current carrying circular loop is
1. circular
2. parabolic
3. hyperbolic
4. straight
Which type of magnet is used to lift heavy loads?
1. horse shoe magnet
2. field magnet
3. bar magnet
4. electromagnet
The type of commutator used to reverse direction of current in a motor is
1. split ring commtator
2. sliding cpommutator
3. Slit ring commutator
4. none of these
Which of the following correctly describes the magnetic field near a long straight wire?
1. The field consists of straight lines perpendicular to the wire.
2. The field consists of straight lines parallel to the wire.
3. The field consists of radial lines originating from the wire.
4. The field consists of concentric circles centred on the wire.
The phenomenon of electromagnetic induction is
1. the process of charging a body.
2. the process of generating magnetic field due to a current passing through a coil.
3. producing induced current in a coil due to relative motion between a magnet and the coil.
4. the process of rotating a coil of an electric motor.
The essential difference between an AC generator and a DC generator is that
1. AC generator has an electromagnet while a DC generator has permanent magnet.
2. DC generator will generate a higher voltage.
3. AC generator will generate a higher voltage.
4. AC generator has slip rings while the DC generator has a commutator.
At the time of short circuit, the current in the circuit
1. reduces substantially.
2. does not change.
3. increases heavily.
4. vary continuously.
The device in which electric motor is not used
1. electric fan
2. washing machine
3. refrigerator
4. none of these
The function of brushes in electric motor is
1. to reverse direction of curent
2. to produce magnetic field
3. to make contact with rotating ring and to supply current to the coil.
4. to produce electric current
The factors on which magnetic field strength produced by solenoid depends upon
1. number of turns
2. magnitude of current
3. nature of core material
4. all of these
A soft iron bar is indroduced inside a solenoid .The magnetic field inside solenoid
1. will remain same
2. will decrease
3. will increase
4. will be infinite
The earth wire carries
1. current
2. voltage
3. potential
4. no current
In all the electrical devices, the switches are put in the
1. live wire
2. earth wire
3. neutral wire
4. none of these
Electric motor converts electric energy into
1. heat energy
2. mechanical energy
3. potential energy
4. kinetic energy
The CGS unit of magnetic induction is
1. ampere per meter
2. tesla
3. tesla
4. gauss
One tesla is also equal to
1. one gauss
2. 10 gauss
3. 10,000 gauss
4. 1/10,000 gauss
The unit magnetic flux is
1. weber
2. Tesla
3. Oersted
4. Horsepower
In a dynamo the direction of electric current is found through
1. right hand rule
2. left hand rule
3. maxwell's rule
4. Ampere's law
What is the colour of the wire used for earthing?
1. green
2. red
3. black
4. blue
Electromagnetic induction was discovered by
1. Tesla
2. Micheal Faraday
3. Ampere
4. H.C. Oersted
The earth is a magnet.This statement is:
1. always true
2. always false
3. sometimes true, sometimes false
4. sometimes false
What is the shape of magnet used in an electric bell?
1. circular
2. triangular
3. U shaped
4. bar magnet
A negative charge is moving away from a person, the direction of magnetic field lines will be in
1. clockwise direction
2. anti-clockwise direction
3. vertically upward direction
4. vertically downward direction

Magnetic effects of Electric Current

Quiz