VBQs Class 10 Science Magnetic Effect of Electric Current

Please refer to VBQs for Class 10 Science Magnetic Effect of Electric Current. All value based questions for English Class 10 have been provided with solutions. We have provided below important values questions and answers. Students should learn these solved VBQs for Class 10 Science as these will help them to gain more marks and help improve understanding of important topics.

Magnetic Effect of Electric Current VBQs Class 10 Science with Answers

Multiple Choice Questions

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.

Question. For a current in a long straight solenoid N- and S-poles are created at the two ends. Among the following statements, the incorrect statement is :
(A) The field lines inside the solenoid are in the form of straight lines which indicates that the magnetic field is the same at all points inside the solenoid.
(B) The strong magnetic field produced inside the solenoid can be used to magnetise a piece of magnetic material like soft iron, when placed inside the coil.
(C) The pattern of the magnetic field associated with the solenoid is different from the pattern of the magnetic field around a bar magnet.
(D) The N and S-poles exchange position when the direction of current through the solenoid is reversed.

Question. A constant current flowing in a horizontal wire in the plane of the paper from East to West is shown in Figure. The direction of magnetic field at a point will be from North to South :

(A) Directly above the wire.
(B) Directly below the wire.
(C) At a point located in the plane of the paper, on the north side of the wire.
(D) At a point located in the plane of the paper, on the south side of the wire.

Question. Which of the following property of a proton can change while it moves freely in a magnetic field? (There may be more than one correct answer.)
(A) Mass
(B) Speed
(C) Velocity
(D) Momentum

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

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.

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.

Question. What is SI unit of magnetic field strength:
(A) Pascal
(B) Nm²
(C) Tesla
(D) No unit

Question. 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.

Question. A momentary deflection is shown by the galvanometer, when

(A) Key K is open
(B) Key K is closed
(C) In both the situations
(D) In neither of the case.

Case Based Questions

An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor’s magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor’s shaft.

Question. In Electric motor magnetic field is produced by
(A) Permanent magnet
(B) Electro magnet
(C) both (a) and (b)
(D) none of the above.

Question. Electric motor is used in
(A) electric fans
(B) refrigerators
(C) mixers
(D) all of the above

Question. Direction of magnetic force on a current carrying conductor placed in magnetic field is given by
(A) Fleming’s left hand rule
(B) Fleming’s right hand rule
(C) Right hand palm rule
(D) none of the above

Question. The commercial motors use
(A) an electromagnet in place of permanent magnet
(B) large number of turns of the conducting wire in the current carrying coil
(C) a soft iron core on which the coil is wound.
(D) All of the above

Question. Moving part of an electric motor is called
(A) brushes
(B) shaft
(C) split ring
(D) slip ring

Short Answer Type Questions

Question. Draw magnetic field lines around a bar magnet.
Answer.

Question. Why don’t two magnetic lines of force intersect each other ?
Answer. The resultant force on a north pole of the compass needle at any point can be only in one direction. But if the two magnetic field lines intersect one another, then the resultant force on the north pole placed at the point of intersection will be along two directions, which is not possible.

Question. List the properties of magnetic lines of force.
Answer. Properties of magnetic lines of force:
By rule the field lines start from the north pole and end at the south pole,
Inside the magnet, the direction of field lines is from south pole to north pole.
The magnetic field lines are closed curves.
The magnetic field is stronger, where the field lines are crowded.
No two field-lines intersect each other.

Question. Consider a circular loop of wire lying on the plane of the table. Let the current pass through the loop clockwise. Apply the right hand rule to find out the direction of the magnetic field inside and outside the loop.

Answer. By applying right hand thumb rule, we find that all the sections produce magnetic field downwards at all points inside the loop while at the outside points, the field is directed upwards. Therefore, the magnetic field acts normally into the plane of the paper at the points inside the loop and normally out of the plane of paper at points outside the loop.

Question. Explain Right Hand Thumb Rule
Answer. Imagine you are holding a current-carrying straight conductor in right hand such that the thumb points towards the direction of current the fingers will wrap around the conductor in the direction of the field lines of the magnetic field. This is known as the right-hand thumb rule

Question. A current through a horizontal power line flows in east to west direction. What is the direction of magnetic field at a point directly below it and at a point directly above it?
Answer. The current is in the east-west direction. Applying the right-hand thumb rule, we get that the magnetic field (at any point below or above the wire) turns clockwise in a plane perpendicular to the wire, when viewed from the east end, and anti-clockwise, when viewed from the west end.

Question. The magnetic field in a given region is uniform. Draw a diagram to represent it.
Answer. A uniform magnetic field in a region is represented by drawing parallel straight lines, all pointing in the same direction. For example, the uniform magnetic field which exists inside a current-carrying solenoid can be represented by parallel straight lines pointing from its S-pole to N-pole

Question. When is the force experienced by a current-carrying conductor placed in a magnetic field largest?
Answer. When the conductor carries current in a direction perpendicular to the direction of the magnetic field, the force experienced by the conductor is largest.

Question. Name two safety measures commonly used in electric circuits and appliances.
Answer. (i) Earthing and (ii) Electric fuse.

Question. State Fleming’s left hand rule.
Answer. Fleming’s left hand rule : Stretch the first finger, the middle finger and the thumb of your left hand mutually perpendicular to each other in such a way that the first finger represents the direction of the magnetic field, the middle finger represents the direction of the current in the conductor, then the thumb will represent the direction of Force(motion of the conductor).

Question. What is an electromagnet? What are the factors that decide the strength of the electromagnet?
Answer. The strong magnetic field produced inside a solenoid can be used to magnetize a piece of magnetic material, like soft iron, when placed inside the coil The magnet so formed is called an electromagnet. The strength of the electromagnet depends on:
i) Amount of current flowing through it
ii) No of turns in the coil (solenoid)
iii) Nature of the core.

Question. What is the role of the split ring in an electric motor?
Answer. The split ring reverses the direction of current in the armature coil after every half rotation, i.e., it acts as a commutator. The reversed current reverses the direction of the forces acting on the two arms of the armature after every half rotation. This allows the armature coil to rotate continuously in the same direction.