Describe Magnetic Field due to a Current in a Solenoid || what is FORCE ON A CURRENT CARRYING CONDUCTOR IN A MAGNETIC FIELD || how electric motor work

*Magnetic Field due to a Current in a Solenoid

A coil of numerous circular turns of protects copper wire wrapped closely within the shape of a barrel is called a solenoid. The design of the attractive field lines around a current-carrying solenoid is appeared in Fig. (4).

Figure-(4). Field lines of the magnetic field through and around a current carrying solenoid.

Compare the design of the field with the attractive field around a bar magnet. Do they see comparative? Yes, they are comparative. In reality, one conclusion of the solenoid carries on as a attractive north post, whereas the other carries on as the south post. The field lines interior the solenoid are within the shape of parallel straight lines. This shows that the attractive field is the same at all points inside the solenoid. That's , the field is uniform interior the solenoid.

             A solid attractive field delivered interior a solenoid can be utilized to charge a bit of attractive fabric, like delicate press, when put interior the coil (Fig. 5). The magnet so shaped is called an electromagnet.

Fig. 5 A current-carrying solenoid coil is utilized to charge steel bar interior it – an electromagnet.


We have learnt that an electric current streaming through a conductor produces a attractive field. The field so created applies a constrain on a magnet put within the region of the conductor. French researcher Andre Marie Ampere (1775–1836) recommended that the magnet must moreover apply an rise to and inverse drive on the current-carrying conductor. The drive due to a attractive field acting on a current-carrying conductor can be illustrated through the taking after action.

The uprooting of the bar within the over movement recommends that a constrain is applied on the current-carrying aluminum pole when it is put in a attractive field. It too recommends that the direction of constrain is additionally turned around when the course of current through the conductor is switched. Presently alter the course of field to vertically downwards by intercity the two posts of the magnet. It is once once more watched that the heading of drive acting on the current-carrying pole gets turned around. It appears that the heading of the drive on the conductor depends upon the heading of current and the heading of the attractive field. Tests have appeared that the uprooting of the bar is biggest (or the size of the drive is the most elevated) when the course of current is at right points to the heading of the attractive field. In such a condition we will utilize a basic run the show to discover the course of the constrain on the conductor.

we considered the course of the current which of the attractive field opposite to each other and found that the drive is opposite to both of them. The three headings can be outlined through a straightforward run the show, called Fleming’s left-hand run the show. Agreeing to this run the show, extend the thumb, index finger and center finger of your cleared out hand such that they are commonly opposite (Fig. 6). In case the primary finger focuses within the heading of attractive field and the moment finger within the heading of current, at that point the thumb will point within the course of movement or the drive acting on the conductor.

Fig. 6 Fleming’s left-hand rule

Gadgets that utilize current-carrying conductors and attractive areas incorporate electric engine, electric generator, amplifiers, amplifiers and measuring rebellious. Within the another few segments we might consider around electric engines and generators.

More to Know!

Magnetism in medicine

An electric current always produces a magnetic field. Even weak ion currents that travel along the nerve cells in our body produce magnetic fields. When we touch something, our nerves carry an electric impulse to the muscles we need to use. This impulse produces a temporary magnetic field. These fields are very weak and are about one-billionth of the earth’s magnetic field. Two main organs in the human body where the magnetic field produced is significant, are the heart and the brain. The magnetic field inside the body forms the basis of obtaining the images of different body parts. This is done using a technique called Magnetic Resonance Imaging (MRI). Analysis of these images helps in medical diagnosis. Magnetism has, thus, got important uses in medicine.


An electric engine could be a turning gadget that changes over electrical vitality to mechanical vitality. Electric engine is utilized as an vital component in electric fans, fridges, blenders, washing machines, computers, MP3 players etc. Do you know how an electric engine works?

An electric engine, as appeared in Fig. 7, comprises of a rectangular coil ABCD of protects copper wire. The coil is put between the two posts of a attractive field such that the arm AB and CD are opposite to the course of the attractive field. The closes of the coil are associated to the two parts P and Q of a part ring. The internal sides of these parts are protects and joined to an hub. The outside conducting edges of P and Q touch two conducting stationary brushes X and Y, separately, as appeared within the Fig. 7.

Fig. 7 A simple electric motor

Current within the

 coil ABCD enters from the source battery through conducting brush X and streams back to the battery through brush Y. Take note that the current in arm AB of the coil streams from A to B. In arm CD it streams from C to D, that's , inverse to the course of current through arm AB. On applying Fleming’s cleared out hand run the show for the course of drive on a current-carrying conductor in a attractive field (see Fig. 7). We discover that the drive acting on arm AB pushes it downwards whereas the drive acting on arm CD pushes it upwards. Hence the coil and the pivot O, mounted free to turn almost an pivot, pivot anti-clockwise. At half revolution, Q makes contact with the brush X and P with brush Y. In this manner the current within the coil gets switched and streams along the way DCBA. A gadget that turns around the heading of stream of current through a circuit is called a commutator. In electric engines, the part ring acts as a commutator. The inversion of current moreover inverts the course of constrain acting on the two arms AB and CD. Hence the arm AB of the coil that was prior pushed down is presently pushed up and the arm CD already pushed up is presently pushed down. Subsequently the coil and the hub turn half a turn more within the same heading. The switching of the current is rehashed at each half turn, giving rise to a ceaseless turn of the coil and to the axle.

       The commercial engines utilize (i) an electromagnet in put of lasting magnet; (ii) huge number of turns of the conducting wire within the current- carrying coil; and (iii) a delicate press center on which the coil is wound. The delicate press center, on which the coil is wound, also the coils, is called an armature. This improves the control of the engine.


We have considered that when a current-carrying conductor is set in a attractive field such that the course of current is opposite to the attractive field, it encounters a drive. This drive causes the conductor to move. Presently let us envision a circumstance in which a conductor is moving interior a attractive field or a attractive field is changing around a settled conductor. What will happen? This was to begin with examined by English physicist Michael Faraday. In 1831, Faraday made an imperative breakthrough by finding how a moving magnet can be utilized to create electric streams. To watch this impact, let us perform the taking after activity.

            You'll be able too check that in case you had moved south post of the magnet towards the conclusion B of the coil, the avoidances within the galvanometer would fair be inverse to the past case. When the coil and the magnet are both stationary, there's no avoidance within the galvanometer. It is, hence, clear from this movement that movement of a magnet with respect to the coil produces an actuated potential distinction, which sets up an initiated electric current within the circuit.

     The initiated current is found to be the most elevated when the course of movement of the coil is at right points to the attractive field. In this circumstance, able to utilize a basic run the show to know the course of the initiated current. Extend

the thumb, pointer and center finger of right hand so that they are opposite to each other, as appeared in Fig. 8. In the event that

 the index finger demonstrates the heading of the attractive field and the thumb appears the heading of movement of conductor, at that point the center finger will appear the heading of actuated current. This basic rule the show is called Fleming’s right-hand rule.

Fig. 8 Fleming’s right-hand rule

    Some related questions:-

What is magnetic effect of electric current for class 10th?

Ans. What is a Magnet? According to magnetic effects of electric current class 10, a magnet is an object that attracts or repels other magnetic materials (such as objects made of iron, cobalt and nickel) with its magnetic field. Properties of a magnet: When suspended freely, a magnet rests in a north – south direction.

What is the definition of magnetic effect of current?

Ans. Magnetic effect of electric current - " The production of magnetic field around a conducting wire when electric current is allowed to flow through it, is called magnetic field of electric current."

What is magnetic effect of electric current examples?

Ans.A solenoid is a cylindrical coil of wire that behaves like a bar magnet when current flows through it. If we insert a piece of iron in a coil carrying current, then iron gets strongly magnetised. This principle is used to make strong electromagnets.

What is the effect of electric current?

Ans.When current flows in a circuit it exhibits various effects. The main effects are heating, chemical and magnetic effects. The main effects are heating, chemical and magnetic effects.

What is chemical effect of electric current?

Ans. The passage of an electric current through a conducting solution causes chemical reactions. As a result, bubbles of a gas may be formed on the electrodes. Deposits of metal may be seen on electrodes. Changes of colour of solutions may occur. The reaction would depend on what solution and electrodes are used.

What is electric effect?

Ans.A large part of this field deals with the study of chemical changes caused by the passage of an electric current (electrolytic processes) and the production of electrical energy by chemical reactions (Galvanic or Voltaic processes).

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