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प्रश्न
Name the material of core in (a) an electric bell, (b) electromagnet, (c) a d.c. motor, (d) an a.c. generator and (e) a transformer.
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उत्तर
Soft iron is used in all.
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संबंधित प्रश्न
Name the material used for making the armature of an electric bell. Give a reason for your answer.
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 ______.
The magnetic flux through a coil having 100 turns decreases from 5 milli weber to zero in 5 second. Calculate the e.m.f. induced in the coil.
What is an electromagnet?
Answer the following in short.
Name a few common appliances that use electromagnets.
Describe briefly one way of producing an induced current in a coil. State one factor that determines the magnitude of induced e.m.f.
State the condition when an electric charge can give rise to a magnetic field.
State the factors that can increase the speed of rotation of the coil in a D.C. motor.
A current-carrying solenoid is suspended so as to freely rotate in a horizontal plane. State in what direction will it rest. Give a reason for your answer.
or
When a solenoid that is carrying current is freely suspended, it comes to rest in a particular direction. Why does this happen?
How does a magnetic field set up by a solenoid change when cross-sectional area of solenoid is increased?
