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

Assertion-Reason Type Questions 

For question numbers 1 and 2 two statements are given-one labeled as Assertion (A) and the other labeled Reason (R). Select the correct Answer: to these questions from the codes (a), (b), (c) and (d) as given below:
(a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the Assertion.
(b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the Assertion.
(c) ‘A’ is true but ‘R’ is false.
(d) ‘A’ is false but ‘R’ is true.

Question: Overloading is due to
a) Insulation of wire is damaged
b) Fault in the appliances
c) Accidental hike in supply voltage
d) All the above.
Answer: d

Question: The magnetic field near a long straight wire is described by
a) Straight field lines parallel to the wire.
b) Straight field lines perpendicular to the wire.
c) Concentric circles centered on the wire.
d) Radial field lines starting from the wire.
Answer: c

Question: The most important safety method used for protecting home appliances from short circuiting or overloading is
a) Earthing
b) Use of fuse
c) Use of stabilizers
d) Use of electric meter
Answer: a

Question: The essential difference between A.C. generator and a D.C. generator is that
a) A.C. generator has an electromagnet while a D.C. generator has permanent magnet.
b) D.C. generator will generate a higher voltage.
c) A.C. generator will generate a higher voltage.
d) A.C. generator has slip rings while the D.C. generator has commutator.
Answer: d

Question: The device used for producing electric current is called
a) Generator
b) Galvanometer
c) Ammeter
d) Motor
Answer: a

Question: Earth wire carries
a) Current
b) Voltage
c) No current
d) None of the above.
Answer: c

Question: The strength of magnetic field inside a long current-carrying straight solenoid is
a) More at the ends than at the centre
b) Minimum in the middle
c) Same at all points
d) Found to increase from one end to other.
Answer: b

Question: To convert an AC generator into DC generator
a) Split ring type commutator must be used
b) Slip rings and brushes must be used
c) A stronger magnetic field has to be used
d) A rectangular wire loop has to be used.
Answer: a

Question: Forces acting on a stationary charge in the magnetic field B is
a) BQv
b) BQ/v
c) Bv/Q
d) Zero
Answer: d

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

Question: Which are the characteristics of fuse element?
a) High conductivity
b) Low melting point
c) Do not burn due to oxidation
d) All of the above.
Answer: b

Question: The main advantage of AC power transmission over DC power transmission over long distance is
a) AC transmits without much loss of energy
b) Less insulation problem
c) Less problem of instability
d) Easy transformation
Answer: a

Question: The factors on which magnetic field strength produced by current-carrying solenoid depends are
a) Magnitude of current
b) Number of turns
c) Nature of core material
d) All of the above
Answer: d

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 induction
d) None of the above
Answer: b

Question: Who has stated the Right Hand Thumb Rule?
a) Oersted
b) Fleming
c) Maxwell
d) Einstein
Answer: c

Question: A.C. generator works on the principle of
a) Force experienced by a conductor in magnetic field
b) Electromagnetic induction
c) Electrostatic
d) Force experienced by a charged particle in electric field
Answer: b

Question: Which of the following factors affect the strength of force experienced by a current-carrying conductor in a uniform magnetic field?
a) Magnetic field strength
b) Magnitude of current in a conductor
c) Length of the conductor within magnetic field
d) All of the above
Answer: d

Question: Choose the correct option:
a) The magnetic field inside a long straight solenoid-carrying current 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: Which of the following properties of a proton can change when it moves freely in a magnetic field?
a) Mass
b) Speed
c) Velocity
d) Momentum
Answer: c

Question: The nature of magnetic field line passing through the centre of current-carrying circular loop is
a) Circular
b) Ellipse
c) Parabolic
d) Straight line
Answer: a

Question: The most important safety device method used for protecting electrical appliances from short circuiting or overloading is
a) Earthing
b) Use of stabilizer
c) Use of electric meter
d) Fuse
Answer: d

Question: The phenomenon 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 at an electric motor
Answer: c

Question: A magnet is moved towards a coil (i) quickly (ii) slowly. The induced potential difference is
a) More in (i) than in (ii) case
b) More in (ii) than in (i) case
c) Same in both
d) Can’t say
Answer: a

Question: Magnetic field lines determine
a) The shape of magnetic field
b) Only the direction of magnetic field
c) Only the relative strength of the magnetic field
d) Both the direction and the relative strength of magnetic field
Answer: d

Question: At the time of short circuit, the current in the circuit
a) Reduce substantially
b) Does not change
c) Increases heavily
d) Varies continuously
Answer: c

Question: A current carrying conductor placed in magnetic field experiences a force. The displacement of the conductor in magnetic field can be increased by
a) Decreasing the magnetic field
b) Decreasing the current in the conductor
c) Increasing the magnetic field
d) None of the above
Answer: c

Question: Fleming’s left hand rule and right hand rule are used in
a) Generator and electric motor
b) Electric motor and generator
c) Any rule can be used for any device
d) Both are applicable for generator and motor
Answer: b

Question: The instrument used to detect the electric current in the circuit is known as
a) Galvanometer
b) Ammeter
c) Voltmeter
d) Odometer
Answer: a

Question: Electric motor converts
a) Mechanical energy into electrical energy
b) Mechanical energy into heat energy
c) Electrical energy into heat energy
d) Electrical energy into mechanical energy
Answer: d

Question: A positively charged particle (alpha-particle) 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: Potential difference between a live wire and a neutral wire is
a) 200 volt
b) 150 volt
c) 210 volt
d) 220 volt
Answer: d

Question: Which one of the following 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 centered on the wire
Answer: d

Question: A device for producing electric current is called a
a) Galvanometer
b) Motor
c) Generator
d) Ammeter
Answer: c

Question: A soft iron bar is introduced inside the current carrying solenoid. The magnetic field inside the solenoid
a) Will increase
b) Will remain the same
c) Will decrease
d) Will become zero
Answer: d

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

Question: A positively charged particle projected towards west is deflected toward north by a magnetic field. The direction of the magnetic field is
a) Upward
b) Downward
c) Towards south
d) Towards east
Answer: d

Question: Concentric circles with arrows centered at the wire AB are shown in figure.
a) No current in AB
b) Current flows from B to A
c) Current flows from A to B
d) None of these
Answer: b

Question: Which of the following properties of a proton can change while it moves freely in a magnetic field?
a) Mass
b) Speed
c) Velocity
d) Momentum
Answer: c, d

Question: We can induce the current in a coil by
a) Moving the coil in a magnetic field
b) Changing the magnetic field around it
c) Changing the orientation of the coil in the magnetic field
d) All the above
Answer: a

Question: Inside the magnet, the field lines move
a) From north to south
b) From south to north
c) Away from south pole
d) Away from north pole
Answer: b

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 to the square of the distance from wire
Answer: b

Question: By which instrument can the presence of magnetic field be determined?
a) Magnetic needle
b) Ammeter
c) Galvanometer
d) Voltmeter
Answer: a

Question: The pattern of the magnetic field produced by a straight current-carrying conductor is
a) In the direction opposite to the current
b) In the direction parallel to the wire
c) Circular around the wire
d) In the same direction of current
Answer: c

Question: What should be the core of an electromagnet?
a) Soft iron
b) Hard iron
c) Rusted iron
d) None of the above
Answer: a