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प्रश्न
What is dynomo (a.c. generator)? State the principle on which it works.
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उत्तर
Dynamo (or a.c. generator) is a device which converts mechanical energy into electrical energy. It works on the principle of electromagnetic induction.
संबंधित प्रश्न
State two ways of magnetising an iron piece?
Name two factors on which the strength of magnetic field of an electromagnet depends and state how does it depend on the factors stated by you.
State two differences between an electromagnet and a permanent magnet.
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.
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 ______.
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.
A straight wire is held vertical and current is passed in it in the upward direction. A compass needle is kept near the wire in north of it. How is the needle deflected? What is the change in the deflection of the needle if the current in wire is reversed?
What will be the effect on the working of an electric bell if instead of a direct current an alternating current is used?
Write the answer in your words.
How is an electromagnet made?
