Advertisements
Advertisements
प्रश्न
State the function of a split ring in D.C. motor.
उत्तर
When the coil of a D. C motor turns through 180°, the split ring reverses the direction of the current in the coil from CBAD to DABC.
In this way, the coil continues to rotate continuously in the same direction and positive and negative polarities are maintained.
APPEARS IN
संबंधित प्रश्न
Name and state the rule by which polarity at the ends of a current carrying solenoid is determined.
What is an electric motor?
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.?
Complete the following sentence :
On reserving the direction of current in a wire, the magnetic field produced by it gets _____.
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.
State two advantages of an electromagnet over a bar magnet.
What energy conversion takes place during the working of a d c motor?
The primary windings of a step-up transformer are usually made of thicker wire than the secondary. Explain.
How does a magnetic field set up by a solenoid change when cross-sectional area of solenoid is increased?