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

Question: Which of the following is not attracted by a magnet?
a) Steel
b) Cobalt
c) Brass
d) Nickel
Answer: c

Question: The magnetic effect of current was discovered by:
a) Maxwell
b) Fleming
c) Oersted
d) Faraday
Answer: c

Question: An induced e.m.f. is produced when a magnet is plunged into a coil. The strength of the induced e.m.f. is independent of
a) the strength of the magnet
b) number of turns of coil
c) the resistivity of the wire of the coil
d) speed with which the magnet is moved
Answer: c

Question: The magnetic lines of force, inside a current carrying solenoid, are
a) along the axis and are parallel to each other
b) perpendicular to the axis and equidistance from each other
c) circular and they do not intersect each other
d) circular at the ends but they are parallel to the axis inside the solenoid
Answer: a

Question: The shape of the earth’s magnetic field resembles that of an imaginary:
a) U-shaped magnet
b) Straight conductor carrying current
c) Current-carrying circular coil
d) Bar magnet
Answer: b

Question: The value of magnetic field due to a small element of current carrying conductor at a distance r and lying on the plane perpendicular to the element of conductor is
a) zero
b) maximum
c) inversely proportional to the current
d) none of the options
Answer: b

Question: A current carrying wire in the neighborhood produces
a) no field
b) electric and magnetic fields
c) electric field only
d) magnetic field only
Answer: d

Question: A 3-pin mains plug is fitted to the cable for a 1 kW electric kettle to be used on a 250 V a.c. supply. Which of the following statement is not correct?
a) The fuse should be fitted in the live wire
b) A 13 A fuse is the most appropriate value to use
c) The neutral wire is coloured black
d) The green wire should be connected to the earth pin
Answer: b

Question: Two identical coaxial circular loops carry a current i each circulating in the same direction. If the loops approach each other, you will observe that
a) the current in each increases
b) the current in each decreases
c) the current in each remains the same
d) the current in one increases whereas that in the other decreases
Answer: b

Question: The axis of earth’s magnetic field is inclined with the geographical axis at an angle of about:
a) 5°
b) 15°
c) 25°
d) 35°
Answer: b

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) 5 A
b) 3 A
c) 1 A
d) 2 A
Answer: d

Question: The magnetic lines of force produced by a bar magnet:
a) originate from the south pole and end at its north pole
b) originate from the north pole and end at its east pole
c) originate from the north pole and end at its south pole
d) originate from the south pole and end at its west pole
Answer: c

Question: Which of the following determines the direction of magnetic field due to a current carrying conductor?
a) Faraday’s laws of electromagnetic induction
b) Fleming’s left-hand rule
c) Lenz’s rule
d) Maxwell’s cork screw rule
Answer: d

Question: When an electron beam is moving in a magnetic field, then the work done is equal to the
a) charge of electron
b) magnetic field
c) product of electronic charge and the magnetic field
d) zero
Answer: d

Question: The direction of magnetic lines of forces close to a straight conductor carrying current will be
a) along the length of the conductor
b) radially outward
c) circular in a plane perpendicular to the conductor
d) helical
Answer: c

Question: Which one of the following substances is the magnetic substance?
a) Mercury
b) Iron
c) Gold
d) Silver
Answer: b

Question: The value of intensity of magnetic field at a point due to a current carrying conductor depends
a) Only on the value of current
b) Only on a small part of length of conductor
c) On angle between the line joining the given point to the mid point of small length and the distance between the small length and the given point
d) On all of the above
Answer: d

Question: The laws of electromagnetic induction have been used in the construction of a
a) galvanometer
b) voltmeter
c) electric motor
d) generator
Answer: d

Question: Along the direction of current carrying wire, the value of magnetic field is
a) zero
b) infinity
c) depends on the length of the wire
d) uncertain
Answer: a

Question: A strong bar magnet is placed vertically above a horizontal wooden board. The magnetic lines of force will be:
a) only in horizontal plane around the magnet
b) only in vertical plane around the magnet
c) in horizontal as well as in vertical planes around the magnet
d) in all the planes around the magnet
Answer: d

Question: A metal sheet is placed in a variable magnetic field which is increasing from zero to maximum. Induced current flows in the directions as shown in figure. The direction of magnetic field will be –
a) normal to the paper, inwards
b) normal to the paper, outwards
c) from east to west
d) from north to south
Answer: b

Question: In an electric motor, the energy transformation is
a) from electrical to chemical
b) from chemical to light
c) from mechanical to electrical
d) from electrical to mechanical
Answer: d

Question: The current in the armature of a motor is reversed every half cycle due to the action of a(n)
a) armature
b) field coil
c) brush
d) commutator
Answer: d

Question: Direction of induced e.m.f. is determined by –
a) Fleming’s left hand rule
b) Fleming’s right hand rule
c) Maxwell’s rule
d) Ampere’s rule of swimming
Answer: b

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

Question: The magnetic field lines:
a) intersect at right angles to one another
b) intersect at an angle of 45° to each other
c) do not cross one another
d) cross at an angle of 60° to one another
Answer: c

Question: The magnetic field lines in the middle of the current-carrying solenoid are:
a) circles
b) spirals
c) parallel to the axis of the tube
d) perpendicular to the axis of the tube
Answer: b

Question: The north pole of earth’s magnet is in the:
a) geographical south
b) geographical east
c) geographical west
d) geographical north
Answer: a

Question: A current carrying loop lying in a magnetic field behaves like a:
a) A magnetic dipole
b) magnetic pole
c) magnetic material
d) non-magnetic material
Answer: a

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 of an electric motor
Answer: c

Question: The device used for producing electric current is called a:
a) generator
b) galvanometer
c) ammeter
d) motor
Answer: a

Question: The force experienced by a current-carrying conductor placed in a magnetic field is the largest when the angle between the conductor and the magnetic field is:
a) 45°
b) 60°
c) 90°
d) 180°
Answer: c

Question: In an electric motor, conversion takes place of
a) Chemical energy into electrical energy
b) Electrical energy into mechanical energy
c) Electrical energy into light
d) Electrical energy into chemical energy
Answer: b

Question: The force exerted on a current-carrying wire placed in a magnetic field is zero when the angle between the wire and the direction of magnetic field is:
a) 45°
b) 60°
c) 90°
d) 180°
Answer: d

Question: The current in a generator armature is AC because
a) the magnetic field reverses at intervals
b) the current in the field coils is AC
c) the rotation of the armature causes the field through it to reverse
d) the commutator feeds current into it in opposite directions every half cycle
Answer: c

Question: The earth wire should be connected to the…………..of an appliance.
Answer: body

Question: For a current-carrying solenoid, the magnetic field is like that of a……………
Answer: bar magnet

Question: If a coil is viewed from one end and the current flows in an anticlockwise direction, then this end is a………pole.
Answer: north

Question: If fuses of 250 mA, 500 mA, 1 A, 5 A and 10 A were available, which one would be the most suitable for protecting an amplifier rated at 240 V, 180 W ?
Answer: 1 A

Question: When a wire is moved up and down in a magnetic field, a current is induced in the wire. What is this phenomenon known as ?
Answer: Electromagnetic induction

Question: Magnetic field lines leave the……….pole of a bar magnet and enter at its……..pole.
Answer: north ; south

Question: A generator with commutator produces………..current.
Answer: direct

Question: Name the rule which gives the direction of induced current.
Answer:Fleming’s right-hand rule

Question: When current is ‘switched on’ and ‘switched off’ in a coil, a current is induced in another coil kept near it. What is this phenomenon known as ?
Answer: Electromagnetic induction

Question: A fuse should always be placed in the ………….wire of a mains circuit.
Answer: live

Question: What type of generator is used at Power Stations ?
Answer:A.C. generator (or Alternator)

Question: If a coil is viewed from one end, and the current flows in a clockwise direction, then this end is a ….. pole.
Answer: south

Question: In which wire in an A.C. housing circuit is the switch introduced to operate the lights ?
Answer: Live wire