CBSE Class 10 Science Magnetic Effects of Electric Current MCQs Set 03

Question. Which of the following properties of a proton can change while it moves freely in a magnetic field? 
(a) Mass
(b) Speed
(c) Momentum
(d) Kinetic energy.
Answer : C

Question. On which of the following does not exert any force when kept in uniform magnetic field? 
(a) Moving magnet
(b) Moving charge
(c) Stationary magnet
(d) Stationary charge
Answer : D

Question. The direction of magnetic field around a straight conductor carrying current can be determined by 
(a) Fleming’s left hand rule
(b) Lenz’s law
(c) Right hand thumb rule
(d) Fleming’s right hand rule.
Answer : C

Question. When is the force experienced by a currentcarrying conductor placed in a magnetic field largest? 
(a) At 30°
(b) at 60°
(c) At 45°
(d) at 90°
Answer : D

Question. An electric motor is a device which transform : 
(a) mechanical anergy to electrical energy
(b) heat energy to electrical energy
(c) electrical energy to heat energy
(d) electrical energy to mechanical energy.
Answer : D

Question. An electric charge in uniform motion produces 
(a) an electric field only
(b) a magnetic field only
(c) both electric and magnetic fields
(d) no such field at all
Answer : C

Question. Three rings P, Q and R are dropped at the same time over identical hollow magnets as shown here. 

Which of the following describes the order in which the ring P, Q and R reach the bottom of the magnet?
(a) They arrive in the order, P, Q, R.
(b) They arrive in the order P, R, Q
(c) Rings P and R arrive simultaneously, followed by Q
(d) Rings Q and R arrive simultaneously, followed by P.
Answer : B

Question. Which of the following instruments works by electromagnetic induction? 
(a) Dynamo.
(b) Moving coil galvanometer.
(c) Telephone receiver.
(d) Simple motor.
Answer : A

Question. Choose the incorrect statement from the following regarding magnetic lines of field: 
(a) The direction of magnetic field at a point is taken to be the direction in which the north pole of a magnetic compass needle points.
(b) Magnetic field lines are closed curves.
(c) If magnetic field lines are parallel and equidistant, they represent zero field strength.
(d) Relative strength of magnetic field is shown by the degree of closeness of the field lines.
Answer : C

Question. A positively-charged particle (alphaparticle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is 
(a) towards south
(b) towards east
(c) downward
(d) upward
Answer : D

Question. The phenomena of electromagnetic induction is 
(a) the process of charging a body
(b) the process of generating magnetic field due to a current passing through a coil
(c) producing induced current in a coil due to relative motion between a magnet and the coil
(d) the process of rotating a coil of an electric motor.
Answer : C

Question. Direction of rotation of a coil in electric motor is determined by
(a) fleming’s right hand rule
(b) fleming’s left hand rule
(c) faraday law of electromagnetic inductors
(d) None of above
Answer :  B

Question. Which color wire is used for earthing ?
(a) Red
(b) Blue
(c) Green or yellow
(d) none of these
Answer :  C

Question. Who has stated the Right hand Thumb Rule?
(a) Orsted
(b) Fleming
(c) Einstein
(d) Maxwell
Answer : D

Question. What happens to the current in short circuit?
(a) reduces substantially
(b) does not change
(c) increases heavily
(d) vary continuously
Answer :  C

Question : In India the potential difference between live wire and neutral wire is
(a) 240 V
(b) 250 V
(c) 280 V
(d) 220 V.
Answer :  D

Question. Which among of these are the main characteristics of fuse element?
(a) High conductivity
(b) low melting point
(c) do not bum due to oxidation
(d) All of the above
Answer :  D

Question. On increasing number of turns magnetic field of a solenoid:
(a) Decrease
(b) Increase
(c) no effects
(d) none of these
Answer : B

Question. The magnetic field is the strongest at
(a) middle of the magnet.
(b) north pole.
(c) south pole.
(d) both poles.
Answer :  D

Question. Alnico is an alloy of:
(a) AL, Co, Fe
(b) Mg, Al, Zn, Co
(c) Co, Ni, Al
(d) Al, Ni, Sn
Answer :  C

Question. The strength of magnetic field around a current carrying conductor is
(a) inversely proportional to the current but directly proportional to the square of the distance from wire.
(b) directly proportional to the current and inversely proportional to the distance from wire.
(c) directly proportional to the distance and inversely proportional to the current
(d) directly proportional to the current but inversely proportional the square of the distance from wire.
Answer :  B

Question. The mains power supply of a house is through a 2A fuse. How many 50W bulbs can be used in this house at the normal voltage?
(a) 7
(b) 8
(c) 5
(d) 6
Answer :  B

Question. A magnetic field line is used to find the direction of:
(a) South-north
(b) A compass needle
(c) A bar magnet
(d) Magnetic field
Answer :  D

Question. The most suitable material for making the core of an electromagnet is:
(a) Soft iron
(b) Brass
(c) Aluminium
(d) Steel
Answer :  A

Question. Which of the given correctly describes the magnetic field near a long straight wire?
(a) The field consists of straight lines perpendicular to the wire
(b) The field consists of straight lines parallel to the wire
(c) The field consists of radial lines originating from the wire
(d) The field consists of concentric circles centred on the wire
Answer :  D

Question. Current that does not change its direction after equal intervals of time is called:
(a) direct current
(b) indirect current
(c) Alternating current
(d) Static electricity
Answer :  A

Question. The front face of a circular wire carrying current behaves like a north pole. The direction of current in this face of the circular wire is:
(a) Clockwise
(b) Downwards
(c) Anticlockwise
(d) Upwards
Answer :  C

Question. A rectangular coil of copper wire is rotated in a magnetic field) The direction of induced current changes once in each:
(a) Two revolutions
(b) One revolution
(c) Half revolution
(d) One-fourth revolution
Answer :  C

Question. The frequency of direct current (DC) is:
(a) 0 Hz
(b) 50 Hz
(c) 60 Hz
(d) 100 Hz
Answer :  A

Question. At the time of short circuit the current in the circuit.
(a) reduces substantially
(b) does not change
(c) increases heavily
(d) very continuously.
Answer :  C

Question. Circuit Breaker Device which can be used in place of fuse in domestic electric wiring is called:
(a) CBD
(b) DCB
(c) MCD
(d) MCB
Answer :  D

Question. An electric motor is a device which transforms:
(a) Mechanical energy to electrical energy
(b) Heat energy to electrical only
(c) Electrical energy to heat energy only
(d) Electrical energy to mechanical energy
Answer :  D

Question. A TV set consumes an electric power of 230 watts and runs on 230 volts mains supply. The correct fuse for this TV set is:
(a) Five A
(b) Three A
(c) One A
(d) Two A
Answer :  D

Question. The magnetic field inside a long straight solenoid carrying current:
(a) Is zero
(b) Decreases as we move towards its end
(c) Increases as we move towards its end
(d) Is the same at all points
Answer :  D

Question. How many magnetic poles are there in a current carrying solenoid?
(a) two
(b) four
(c) one
(d) six
Answer : A

Fill in The Blank

Question. In a magnetic field pointing away from you, an electron traveling to the right will experience a force in the ......... direction.
Answer : Downward

Question. Field lines are used to represent a ..........
Answer : Magnetic field

Question. In our houses we receive AC electric power of ......... with a frequency of .........
Answer : 220V, 50 Hz.

Question. The N-pole of a compass points to the .......... pole of a permanent magnet.
Answer : S

Question. Field lines are shown closer together where the magnetic field is .........
Answer : Greater

Question. A metallic wire carrying an electric current has associated with it a .......... field.
Answer : Magnetic

Question. Magnetic field lines emerge from the .......... pole of a solenoid or a permanent magnet.
Answer : North

Question. The phenomenon of production of back e.m.f. in a coil due to flow of varying current through it is called ...........
Answer : Self-induction

Question. A Permanent behaves like a solenoid because both contain currents in the form of ..........
Answer : Circles

Question. Field lines come out of ......... pole while enters from ........... pole.
Answer : North, South

True/False

Question. The induced e.m.f. depends only the turns of the coil.
Answer : False

Question. Fleming’s left hand rule helps us to find the direction of the induced current.
Answer : False

Question. The direction of force on a current carrying conductor placed in a magnetic field cannot be reversing the direction of magnetic field.
Answer : False

Question. The magnitude of induced current can be decreased by increasing the area of cross. section of coil.
Answer : False

Question. An electron does not suffer any deflections while passing through a region. This makes sure that there is no magnetic field in that region.
Answer : True

Question. Energy associated with an electric field is analogous to potential energy whereas the energy associated with the magnetic field is analogous to kinetic energy.
Answer : True

Question. A magnetic field exists in the region surrounding a magnet, in which the force of the magnet can be detected.
Answer : True

Question. An electric generator works on the principle of electromagnetic induction.
Answer : True