(2)

Among the given substances, the iron is the only magnetic substances.

(1)

The figure shows the magnetic lines of forces the solenoid.

(3)

Here, A is a magnetic material on which solenoid as wrapped. As by passing current through it the magnetic material will become an electromagnet.

(4)

According to Maxwell's Cork Screw-Rule, if we consider ourselves driving a cork screw in the direction of current, then the direction of the rotation of cork Screw is the direction of the Magnetic field.

(4)

Cartesian Coordinate system is not an example of the right-hand thumb rule. The cartesian coordinate system is used for representing points in space using three perpendicular axes (X, Y and Z). It does not involve any magnetic field, current or force so the right-hand thumb rule does not apply here.

(3)

Commercial motors do not use permanent magnets because they are weak and do not produce strong magnetic field in the region.

(4)

The process of inducing a current in a coil of wire by placing it in a region of changing magnetic field is electromagnetic induction.

(1)

The core of electromagnet is made of soft iron due to following reasons:
(i) It can be easily magnetised and demagnetised.
(ii) It has low carbon content.
(iii) It has large susceptibility and small retentivity.
(iv) It does not retain its magnetism when the current is switched off.
(v) It is less corrosive.

(3)

Fleming's Right hand rule gives the direction of the induced current.

Stretch the thumb, forefinger and middle finger of right hand so that they are perpendicular to each other. If forefinger indicates the direction of the magnetic field, thumb shows the direction of motion of conductor, then the middle finger will show the direction of induced current. We cannot find out the magnitude of either the induced current or magnetic field by this law.

(3)

Velocity of a proton can change while it moves freely in a magnetic field because each moving charged particle in a magnetic field experiences a force. The direction of force experienced by a positively charged proton can be studied by Fleming’s Left-hand Rule.

The force acting on the proton would change both velocity and momentum when it moves freely in magnetic field. If a charged particle’s velocity is completely parallel to the magnetic field, the magnetic field will not exert any force on the particle, and thus the velocity will remain constant. Whereas, if the force is acting perpendicular to the direction of moving charge, work done will be zero. It means kinetic energy does not change. Hence, we can conclude that the force can change the direction of velocity of the proton but not its speed. Thus, momentum and velocity changes.

(4)

A positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is upward. This can be explained by Fleming’s Left-hand Rule which states that if we stretch our thumb, forefinger and middle finger of our left hand perpendicular to each other in such a way that forefinger points the direction of magnetic field and middle finger points the direction of current then thumb will represent the direction of motion or the force acting on the conductor. Hence, upward is the correct answer.

(3)

The phenomenon of electromagnetic induction is producing induced current in a coil due to relative motion between a magnet and the coil. When a coil is brought near the magnet, and a relative motion is generated between the two by either moving the magnet or the coil, the magnetic flux links through the coil changes. This change in the magnetic flux produces an emf or voltage and hence, subsequent electric current in the coil.

(1)

The direction of force acting on a current carrying conductor placed in a magnetic field can be obtained by Fleming’s left hand rule. According to this rule, when a current-carrying conductor is placed in an external magnetic field, the conductor experiences a force perpendicular to both the field and to the direction of the current flow.

(1)

An electromagnet produces a magnetic field so long as current flows in its coil.

(4)

MRI is a technique used to obtain the image of different body parts by using magnetic field.

(3)

The magnetic field inside a solenoid is proportional to both the applied current and the number of turns per unit length. There is no dependence on the diameter of the solenoid, and the field strength does not depend on the position inside the solenoid, i.e., the field inside is constant.

The magnetic field is nearly uniform field in the center, i.e., inside of a long solenoid and the field outside is weak and divergent.

(3)

Galvanometer is an instrument that is used to detect the presence of the current in the circuit. And when magnet is moved near the coil, the current is induced in the coil.

(4)

According to Fleming's left hand rule stretch the thumb, fore finger and middle finger of your left hand side that they are mutually perpendicular. If the first finger points in the direction of magnetic field and second finger in the direction of current, then thumb will point in the direction of force.

(1)

As both the coils are in the same plane. And induced current is found to be highest when the direction of the coil is at right angle to the magnetic field.

(1)

Using Fleming's left hand rule, the nature of charged particle is positive.

(3)

Force on conductor is calculated using Fleming's left hand rule.

(4)

A permanent magnet does not loose its magnetism even when heated on a flame.

(1)

A electric motor works on the principle of Fleming's left hand rule.

(2)

As induced magnetism takes place, as long as the induced magnet is present.

(2)

By Fleming's left hand rule, we know that the force on the wire is perpendicular to the current in the wire and the magnetic field.
That it, there are only two possibilities for the direction of force i.e., upward or downward.

(3)

Using, electromagnet, the magnetic field strength further increase by, increasing the current. Hence, it will enhance the power of electric motor.

(1)

A.C. generator is used to convert mechanical energy to electrical energy.

(4)

Most essential difference between A.C. generator and D.C. generator is using slip ring in A.C. generator and commutator in D.C. generator.

(3)

A short circuit occurs when circuit current rises rapidly and the electric circuit drown an heavy amount of current from the supply.