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प्रश्न
What is an electromagnet?
उत्तर
An electromagnet is a temporary strong magnet made from a piece of soft iron when current flows in the coil wound around it. It is an artificial magnet.
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संबंधित प्रश्न
State two ways of magnetising an iron piece?
Tick the most appropriate answer.
Which of the following methods is used to magnetize a magnetic without touching it by a magnet?
Name the type of transformer shown in fig . What changes will you observe regarding the brightness of the lamp, if
(a) The no. of turns in the secondary is doubled?
(b) The part X of the transformer is removed?
( c) The core of the transformer is made out of copper?
(d ) The A.C. supply is replaced by D.C.?
Fill in the blanks by writing (i) Only soft iron, (ii) Only steel, (iii) Both soft-iron and steel for the material of core and/or magnet.
Electric bell ______.
State two factors on which the magnitude of an induced e.m.f. in the secondary coils of a transformer depends.
Answer the following in short.
Name a few common appliances that use electromagnets.
What will be the effect on the working of an electric bell if instead of a direct current an alternating current is used?
State the factors, on which depends the magnitude of the force acting on current carrying conductor, when it is kept in a magnetic field perpendicular to it.
Point out three differences between an electromagnet and a bar (or permanent) magnet.
How does a magnetic field set up by a solenoid change when cross-sectional area of solenoid is increased?
