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InterviewSolution
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Whatis an electromagnet? Statethe principle on whichit works. Draw a circuitdiagram to show how a soft iron piece can be transformed into an electromagnet. Writeuses of electromagnet. |
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Answer» Solution :Electromagnet : An electrongnetis a magnet consisting of a longcoil of insulatedcopper wire wound arounda soft iron core in the from of a rod. It is magnetised onlywhen an ELECTRICCURRENTIS passed through the coil . OR An electrongnet is temporary strong magnet and is justa solenoidwith its windingon a soft iron core . Theworking of an electrognet is BASED onthemagnetic effect ofelectric current .  A strong magnetic fieldproduced insidea current - carrying solenoid can be used to magnetise a piece of magnetic material like soft iron , byplacingit insidethe coil / solenoid(figure 13.17) . The magnet soformed is called an electromagnet. ANELECTROMAGNET acquires themagneticproperties onlywhenan electric currentis passed through the solenoid . Once the currentis switchedoff ,it almost loses its magneticproperty as the retentivity( theabilityto retain magnetism) of soft iron is verylow . The strength of the electromagnet depends on : (i) The numberof turns per unit length n of thesolenoid . (ii) ThecurrentI through the solenoid . Uses of electromagnets : (1) Electromagnets are usedin electrical devices such as an electric bell , an electric fan ,TELEGRAPH , an electric train ,an electric motor, genertor etc. (2) They are used for lifting and transporting large masses of iron in the from of girders . (3) They are used in medical paractice forremovingpieces of iron from wounds . |
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