In this section we provides Magnetic Effects of Electric Current Multiple Choice Questions (MCQs) with Solutions for CBSE Class 10. We are confidently hopeful that students would find this content a worthy reinforcement for their Exams.
Magnetic Effect of Electric Current Class 10 MCQ
1. When electric current flows in a wire it produces :
(A) An electric field
(B) Magnetic field
(C) Neither electric field nor magnetic field
(D) Both electric & magnetic field
Ans. (B)
Sol. Electric current flows in a wire produces only magnetic field.
2. If current in the coil decreases, the strength of the magnetic field :
(A) Decreases
(B) Increases
(C) First increases then decreases
(D) Eemains unchanged
Ans. (A)
Sol. With decrease in current magnetic field also decreases.
3. What happens to a moving electron beam when a uniform magnetic field is applied at right angles to it?
(A) The beam is deflected in a circular path
(B) The beam is deflected in a parabolic path
(C) The beam starts oscillating
(D) The beam remains unaffected
Ans. (A)
Sol. Magnetic force is perpendicular to motion of charge particle. So motion will be circular.
4. A magnetic field may :
(A) Change the velocity of a charged particles
(B) Change the speed of a charged particle
(C) Change the K. E. of a charged particle
(D) Stop a moving charged particle
Ans. (A)
Sol. Magnetic force is perpendicular to motion. So it changes direction but not speed, however velocity is changed.
5. When direction of current flowing through electromagnet changes then :
(A) Poles of electromagnet will get exchanged
(B) It will not behave as electromagnet
(C) Its strength will decrease
(D) Nothing can be said
Ans. (A)
Sol. Change in direction of current changes the Polarity of electromagnet.
6. The magnetic field at the centre of a current-carrying circular coil depends on the radius R of the coil as :
(A) R
(B) R2
(C) 1/R
(D) 1/R2
Ans. (C)
Sol. B = \frac{{{\mu _0}I}}{{2R}} \Rightarrow \,B \propto \frac{1}{R}
7. 
In the given figure, force on rod A and rod B are in direction respectively:
(A) Rightward direction, leftward direction
(B) Rightward direction, Rightward direction
(C) Leftward direction, Leftward direction
(D) Leftward direction, Rightward direction
Ans. (A)
Sol. Current in both wires is in same direction so force will be attractive in nature.
8. Fleming’s left hand rule is used to find :
(A) The direction of induced current
(B) Force acting on current carrying conductor placed in magnetic field.
(C) Force acting on a charged particle moving in electric field.
(D) None of these
Ans. (B)
Sol. Fuminga’s left hand rule is used to find force acting on current carrying conductor placed in magnetic field.
9. Direction of force acting on a current carrying conductor kept in a magnetic field is given by :
(A) Fleming’s right hand rule
(B) Fleming’s left hand rule
(C) Lenz’s rule
(D) Faraday’s rule
Ans. (B)
Sol. According to Fleming’s left hand rule.
10. A vertical wire carries current in downward direction. If a magnetic field is applied in North to South direction. Force on wire will act towards :
(A) West
(B) East
(C) North
(D) None of these
Ans. (A)
Sol. Using Fleming’s left hand rule.
11. Which of the following statements is correct regarding the motion of a charged particle in a uniform magnetic field:
(1) Speed of the particle remains constant
(2) Direction of motion of particle changes at every moment
(3) Particle may go undeflected
(4) Motion of the particle may be accelerated
(A) Only 1 and 4 are correct
(B) 1, 2 and 3 are correct
(C) 1, 3 and 4 are correct
(D) All are correct
Ans. (C)
Sol. Magnetic force is q(\mathop v\limits^ \to \times \mathop B\limits^ \to ) so it can only change direction and not speed.
12. The value of the magnetic field at a distance x from a long straight current-carrying conductor is proportional to:
(A) x
(B) x2
(C) 1/x2
(D) 1/x
Ans. (D)
Sol. For a straight wire B = \frac{{{\mu _0}I}}{{2\pi x}}\,\, \Rightarrow \,\,B \propto \frac{1}{x}
13. The unit of induced emf is :
(A) Ampere
(B) Volt
(C) Joule
(D) Electron volt
Ans. (B)
Sol. Unit of induced emf is volt.
14. In given figure, the force on arm BC is :
(A) Inwards (into the paper)
(B) Outwards (out of paper)
(C) Upwards
(D) No force will act on arm BC
Ans. (D)
Sol. Magnetic field and current are parallel so BC feels no force because current is parallel to magnetic field.
15. Fleming’s right hand rule gives :
(A) The magnitude of induced emf
(B) The magnitude of the magnetic field
(C) The direction of induced emf
(D) Both magnitude and direction of the induced emf
Ans. (C)
Sol. Fleming’s right hand side gives direction of induced emf.
16. A dynamo converts :
(A) Mechanical energy into electrical energy
(B) Mechanical energy into light energy
(C) Electrical energy into sound energy
(D) Electrical energy into mechanical energy
Ans. (A)
Sol. A dynamo convert mechanical energy toe electrical energy.
17. Choose the correct statements :
(A) A.C. can be easily converted in to DC by mean of a rectifier.
(B) For electroplating A.C. is preferred over D.C.
(C) D.C. Generator is cheaper than A.C. generator
(D) All of the above
Ans. (A)
Sol. AC can be converted to DC by means of a rectifier.
18. A device used for measuring small currents due to changing the magneitc field is known as :
(A) Galvanometer
(B) Ammeter
(C) Voltmeter
(D) Potentiometer
Ans. (A)
Sol. Galvanometer is a device used for measuring small currents due to a changing the magnetic field.
19. Which is not true :
(A) Poles of magnet are not exactly at ends but are slightly inside
(B) A magnetic pole cannot be isolated
(C) Magnet is weakest at poles
(D) Lode stone is a natural magnet
Ans. (C)
Sol. Magnetism is strongest at poles.
20. Which statement is true :
(A) Electromagnetic induction is the production of an electric current when conductor comes in contact with an electric field
(B) Motor is source of electric current
(C) There are two kinds of current ac and dc.
(D) None of these
Ans. (C)
Sol. Currents are of 2 types i.e. AC and DC.
21. The split ring in motor is called :
(A) Armature
(B) Rotor
(C) Commutator
(D) Core
Ans. (C)
Sol. A slip ring in an electric motor is called commutator.
22. A commutator changes the direction of current in the coil of :
(A) A DC motor
(B) A DC motor and an AC generator
(C) A DC motor and a DC generator
(D) An AC generator
Ans.(C)
Sol. A commulator changes the direction of current in the coil of a DC motor and a DC generator.
23. The magnetic field inside a solenoid is :
(A) Zero
(B) Decreases along the axis
(C) Increases along the axis
(D) Uniform
Ans.(D)
Sol. The magnetic field inside solenoid remains uniform.
24. A direct current flows through a solenoid entering in an anticlockwise sense at end A. The solenoid, when made to float in still water, will :
(A) Have the end A pointing north
(B) Have the end A pointing south
(C) Stay in any position
(D) Move in a straight line with constant velocity
Ans.(A)
Sol. Point A becomes north pole and points towards North.
25. A student developed a project on household electric circuit. In fuse wire he should use a wire having :
(A) High Resistivity, high melting point
(B) Low Resistivity, high melting point
(C) High Resistivity, low melting point
(D) Low Resistivity, low melting point
Ans.(C)
Sol. Fuse wire should have high resistivity and low melting point.
26. If current is flowing anticlockwise in a circular wire, then the direction of magnetic field outside the loop would be:
(A) Inwards
(B) Outwards
(C) Clockwise
(D) Anticlockwise
Ans. (B)
Sol. By right hand thumb rule.
27. Which of the following correctly describes the magnetic field of 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.
Ans. (D)
Sol. 
By right hand thumb rule.
28. 4 students took observations, when a magnetic compass is placed under a current carrying wire carrying current from south to north. Which student has correct observation ?
(A) North is deflecting towards west
(B) South is deflecting towards east
(C) Magnetic compass is not deflecting at all
(D) Deflection is different each time, because its depends on the initial orientation of needle.
Ans. (A)
Sol. As per snow rule when current flows from South to North then North Pole of compass needle deflect towards west.
29. The magnetic field due to a straight current carrying conductor is :
(A) Straight lines
(B) Concentric spheres
(C) Concentric circles
(D) Elliptical
Ans. (C)
Sol. Magnetic field due to a straight current carrying conductor is concentric circles.
30. Which of the given figures is correct :
(A) 
(B) 
(C) 
(D) 
Ans. (B)
Sol. Using left hand rule
31. In the given figure,
If the current in rod AB is increased,
the displacement of rod AB will.
(A) Increase
(B) Decrease
(C) Not be affected
(D) Depend on the direction of current
Ans. (A)
Sol. With increase in current, magnetic strength increases and hence displacement also.
32. A rod carrying current from east to west, experiences a force towards north in magnetic field. The direction of field is :
(A) Towards north
(B) Towards east
(C) Downward
(D) Upwards
Ans. (D)
Sol. Field should be upward 
33. The correct pattern of magnetic field due to straight current carrying conductor is
(A) 
(B) 
(C) 
(D) 
Ans. (A)
Sol. Using Right hand tumb rule.
34. In the following figure, four set of observations are taken. Identify the correct observation.
(A) Magnetic field at point A is outwards, and at B is inwards.
(B) Magnetic field at point A is inwards, and at B is outwards.
(C) Magnetic field at both the points is inwards.
(D) Magnetic field at both the points is outwards.
Ans. (D)
Sol. Using Right hand thumb rule field is in outward direction.
35. A rod carrying current from North to South, experiences a force towards East in magnetic field. The direction of field is :
(A) Towards north
(B) Towards east
(C) Downwards
(D) Upwards
Ans. (C)
Sol. Field is inward 
36. 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.
Ans. (C)
Sol. Electromagnetic induction is the phenomenon of producing induced current or emf in a coil due to relative motion between a magnet and the coil.
37. The device used fro producing electric current is called :
(A) Generator
(B) Galvanometer
(C) Ammeter
(D) Motor
Ans. (A)
Sol. Generator is a deivce used for producing electric current.
38. Two bars of soft iron exactly alike are given. One of them is a magnet. Without using any thing more, how would you find which is a magnet :
(A) By bringing two bars near and noting which one is attracting. The attracting one is a magnet
(B) By bringing two bars near and noting which one is repelling. One which repels is an ordinary iron.
(C) By rubbing one bar with the other and noting which becomes magnet. The bar which is magnetised is an ordinary iron
(D) One bar is placed flat horizontal on the table and the other bar is held vertical with its one end on the middle of first bar. If there is attraction between the two, the vertical bar is magnet otherwise ordinary iron.
Ans. (D)
Sol. Attraction of one bar with others at its mid point proves that it is ordinary iron not a magnet.
39. A bar of soft iron is placed flat on the table. A bar magnet is taken and its south pole is placed on one end of the bar of soft iron. The magnet is held almost vertically. The bar is stroked from one end to the other with magnet. On the other end of the bar, magnet is lifted and again placed on the first end. The end of the bar where the magnet is lifted will be :
(A) South pole
(B) No pole
(C) South and north both type
(D) North pole
Ans. (D)
Sol. Because south pole attracts north pole.
40. The essential difference between an AC generator and DC generator is that :
(A) AC generator has an electromagnet while a DC generator has permanent magnet.
(B) DC generator will generate a higher voltage.
(C) AC generator will generate a higher voltage.
(D) AC generator has slip rings while the DC generator has a commutator.
Ans. (D)
Sol. AC generator has slip rings while the DC generator has a commutator. To get a direct current, a split-rings type commutator must be used.
41. The south pole of a freely suspended magnet points to the :
(A) Geographical south
(B) Geographical north
(C) Slightly left of geographical north
(D) None of these
Ans. (A)
Sol. Towards geographical south magnetic north of earth is present.
42. The source of magnetic field is :
(A) Isolated magnetic pole
(B) Current element
(C) Static electric charge
(D) None of the above
Ans. (B)
Sol. Magnetic filed arises due to flow of current.
43. A permanent magnet attracts :
(A) All substances
(B) Only magnetic substances
(C) Attracts & repels magnetic substances
(D) None of these
Ans. (B)
Sol. Permanent magnet attracts all magnetic materials.
44. A magnetic field line is used to find the direction of :
(A) South-North
(B) A bar magnet
(C) A compass needle
(D) Magnetic field
Ans. (D)
Sol. The direction of magnetic field is given by magnetic field lines of force.
45. Which of the following can be considered as cause of magnetism :
(A) Static charges
(B) Moving charges
(C) A conductor possessing large amount of charge
(D) All are correct
Ans. (B)
Sol. Moving charges produced magnetic field.
46. If we increase the resistance in the following circuit, deflection in magnetic needle will :
(A) Increase
(B) Decrease
(C) Remain unchanged
(D) May increase or decrease
Ans. (B)
Sol. If resistance increases then current decreases and hence diflection of needle also decreases.
47. If a conductor is carrying a current in downward direction, the direction of magnetic field in the right hand side of wire will be :
(A) Downwards
(B) Upwards
(C) Inwards
(D) Outwards
Ans. (D)
Sol. Using right hand thumb rule. 
48. A current is passed through a straight wire. The magnetic field established around it has its lines of forces.
(A) Elliptical
(B) Circular
(C) Oval
(D) Parabolic
Ans. (B)
Sol. Magnetic lines of force are circular in nature.
49. 
Which of the following will behave as north pole, when switch will be closed.
(A) Point A
(B) Point B
(C) Point C
(D) Point D
Ans. (A)
Sol. At North Pole current appears to be in clockwise direction.
50. Electric currents are flowing in wires A and B in the directions shown by arrow in figure.
Choose correct directions of magnetic fields in I, II, III, and IV quadrants.
(A) I, II, inwards III and IV – can’t say
(B) I, III inwards, IV outwards, II – can’t say
(C) IV inwards, II outwards, III and I – cant say
(D) None of these
Ans. (C)
Sol. In II nd quadrant due to both wires magnetic field is in outward direction while in quadrant IV it is in inward direction as per right hand thumb rule.
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