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प्रश्न
State three factors which govern the speed of rotation of an electric motor.
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उत्तर
(i) The strength of current in the coil,
(ii) The number of turns in the coil,
(iii) The strength of the magnetic field.
संबंधित प्रश्न
Name and state the rule by which polarity at the ends of a current carrying solenoid is determined.
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 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.
Electromagnet ______.
A straight current-carrying conductor is kept in a magnetic field. It Experiences a force. State three factors on which the magnitude of force Experienced by the conductor depends. Under what condition will the conductor Experience no force?
How does a magnetic field set up by a solenoid change when strength of current in the solenoid is decreased?
What is a permanent magnet? Give one use of it.
What energy conversion takes place during the working of a d c motor?
State the function of a split ring in D.C. motor.
