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

Question. A tesla is equivalent to a
(a) newton per coulomb
(b) newton per ampere-meter
(c) ampere per newton
(d) newton per ampere-second
Answer : B

Question. Which 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 centred on the wire.
Answer : D

Question. Magnetic field due to a current through a straight conductor depends on
(a) current
(b) distance from the wire
(c) Both (a) and (b)
(d) cross-sectional area of wire
Answer : C

Question. The effective length of the magnet is
(a) the complete length of the magnet
(b) the distance between the two poles of the magnet
(c) the half of the length of the magnet
(d) the square of the length of the magnet
Answer : B

Question. The magnetic field at a distance r from a long wire carrying current I is 0.4. Tesla. The value of magnetic field at a distance 2r is
(a) 0.2 T
(b) 0.1 T
(c) 0.15 T
(d) 1 T
Answer : A

Question. A vertical wire carries a current upward. The magnetic field north of the wire will be directed
(a) upward
(b) eastward
(c) westward
(d) northward
Answer : C

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. By removing the inducing magnet, the induced magnetism is
(a) Finished after some time
(b) Finished just after
(c) Not finished for a long time
(d) Not changed
Answer : B

Question. Which of the following processes will not produce new magnetic poles?
(a) cutting a bar magnet in half
(b) turning on a current in a solenoid
(c) running a current through a straight wire
(d) placing an iron rod in contact with a magnet
Answer : C

Question. Which of the following is not true
(a) Induction precedes attraction
(b) We cannot isolate a single pole
(c) We can magnetise an iron ring
(d) A permanent magnet retains its magnetism even when heated on a flame.
Answer : D

Question. A ship is to reach a place 8c south of west. In what direction should the ship be steered if declination at the place is 18c west?
(a) West of magnetic south at angle 64c
(b) East of magnetic north at angle 64c
(c) West of magnetic south at angle 50c
(d) East of magnetic north at angle 18c
Answer : A

Question. Which of the following statement is not correct about two parallel conductors carrying equal currents in the same direction?
(a) Each of the conductors will repel each other.
(b) The two conductors will repel each other.
(c) The are concentric lines of force around each conductor
(d) Each of the conductors will move if not prevented from doing so
Answer : B

Question. A small magnet is placed perpendicular to a uniform magnet field. The forces acting on the magnet will result in
(a) Rotational motion
(b) Translatory motion
(c) No motion at all
(d) Translational and rotational motion both
Answer : A

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

Question. Three plotting compasses are placed close to a solenoid carrying a current. How many of the compass needles will change direction, if the current through the solenoid is increased? (Ignore the effect of the earth’s magnetic field).
(a) Only 1 compass needle
(b) 2 compass needle
(c) 3 compass needle
(d) None of the above
Answer : D

Question. The magnetic field at a point due to a current carrying
conductor is directly proportional to the
(a) current flowing through to the
(b) Distance from the conductor
(c) Voltage across the conductor
(d) Resistance of the conductor
Answer : A

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. Choose the correct option (s).
The magnetic field inside a long straight solenoidcarrying 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. To avoid risk of electrical shock, which phenomena is used?
(a) Over loading
(b) Short circuiting
(c) Earthing
(d) None of these
Answer : C

Question. Force on a current carrying conductor in a magnetic field depends on
(a) direction of the current
(b) direction of magnetic field
(c) Both (a) and (b)
(d) length of the wire
Answer : C

Question. When the bars of bismuth are placed between the magnetic poles they set their length
(a) perpendicular to the lines of force
(b) along the lines of force
(c) neither perpendicular nor along the lines of force
(d) In any direction
Answer : A

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. Magnetic lines do not intersect on one-another because
(a) they are at a distance
(b) they are in the same direction
(c) they are parallel to another
(d) at the point intersection there will be two direction of the magnetic force which is impossible
Answer : D

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

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 the other
Answer :   C

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

Question. Commercial electric motors do not use
(a) an electromagnet to rotate the armature
(b) effectively large number of turns of conducting wire in the current carrying coil
(c) a permanent magnet to rotate the armature
(d) a soft iron core on which the coil is wound
Answer :   C

Question. In Fleming’s right hand rule direction in induced current is given by:
(a) thumb
(b) middle finger
(c) first finger
(d) none of these
Answer :   B

Question. We can induce the current in a coil by
(a) moving the coil in a magnetic field
(b) by changing the magnetic field around it
(c) by changing the orientation of the coil in the magnetic field
(d) All of above
Answer :  A

Question. A magnetic field directed in north direction acts on an electron moving in east direction. The magnetic force on the electron will act
(a) vertically upwards.
(b) towards east.
(c) vertically downwards.
(d) towards north.
Answer :   C

Question.   Magnetic effect of current was discovered by
(a) Oersted
(b) Faraday
(c) Bohr
(d) Ampere
Answer :  A

Question. No force acts on a current carrying conductor when it is placed-
(a) perpendicular to the magnetic field
(b) parallel to the magnetic field
(c) far away from the magnetic field
(d) inside a magnetic field
Answer :  B

Question. Which of the following statement is not correct about the magnetic field?
(a) Magnetic field lines form a continuous closed curve.
(b) Magnetic field line do not interest each other.
(c) Direction of tangent at any point on the magnetic field line curve gives the direction of magnetic field at that point.
(d) Outside the magnet, magnetic field lines go from South to North pole of the magnet.
Answer :  D

Question. In the magnetic field the force acting on the current carrying conductor will be maximum :
(a) If conductor is parallel to the field
(b) If conductor is perpendicular to the field
(c) If conductor subtends an angle of 60Deg with the field
(d) If conductor subtends an angle of 45deg with the field
Answer :  A

Question. The direction of induced current is given by
(a) Fleming’s right hand rule
(b) Fleming’s left hand rule
(c) Right hand thumb rule
(d) Left hand thumb rule.
Answer :  A

Question. Electric supply in homes and factories is:
(a) 220V and 400V
(b) 400V and 220V
(c) 220V and 440V
(d) 440V and 220V
Answer : C

Question. AC generator works on the principle of
(a) ohnis law
(b) Joule’s law of heating
(c) faraday’s law of electromagnetic induction.
(d) none of the above
Answer :  C

Question. Induced current flows through a coil 
(a) for more than the period during which flux changes through it.
(b) for less than the period during which flux changes through it.
(c) only for the period during which flux changes through it.
(d) none of the above.
Answer : C

Question. If the force exerted on a current carrying wire placed in a magnetic field is zero, then the angle between wire and the direction of magnetic field is 
(a) 45°
(b) 60°
(c) 90°
(d) 180°
Answer : D

Question. A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current change once in each 
(a) two revolutions
(b) one revolution
(c) half revolution
(d) one-fourth revolution.
Answer : C

Question. Four students plotted the sketch of the patterns of magnetic field lines representing the magnetic field around a current carrying straight wire as shown in figures P, Q, R and S. Which one of the following sketches is correct? 

(a) P
(b) Q
(c) R
(d) S
Answer : D